# TDS (Total Dissolved Solids) & It's importance in Shrimp Rearing



## mordalphus (Jun 23, 2010)

Digital, ill sell you one if you want. Never ever buy a test strip for anything unless its fresh litmus paper. Test strips are about as inaccurate as you can get


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## OverStocked (May 26, 2007)

And the meter reads TDS.... the strips are measuring hardness in PPM. They are not the same thing...


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## happi (Dec 18, 2009)

OverStocked said:


> And the meter reads TDS.... the strips are measuring hardness in PPM. They are not the same thing...


am bit confused about the TDS meter, last time i tested, it was reading 250ppm on the meter and API test kit was reading 6dh, now either one is inaccurate. :confused1:


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## MsNemoShrimp (Apr 25, 2011)

Looks like Digital it is : )


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## OverStocked (May 26, 2007)

happi said:


> am bit confused about the TDS meter, last time i tested, it was reading 250ppm on the meter and API test kit was reading 6dh, now either one is inaccurate. :confused1:


They are testing different things... If you get the same results, it is coincidental.


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## happi (Dec 18, 2009)

OverStocked said:


> They are testing different things... If you get the same results, it is coincidental.


so does that mean API results represent real GH, while TDS meter detect other things which does not really represent real GH?


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## mordalphus (Jun 23, 2010)

Yes, tds could be "cleanliness", ro water has close to zero solids disolved in it. Water with nitrates and phosphorus has more solids dissolved.

Reconstituted ro water measured with a tds meter will yield a ppm of hardness, only because you have only the hardener dissolved into the water


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## shrimpnmoss (Apr 8, 2011)

digital all the way...you can use it over and over again...


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## MsNemoShrimp (Apr 25, 2011)

shrimpnmoss said:


> digital all the way...you can use it over and over again...


And its only $9 shipped to your door! :biggrin:


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## BradH (May 15, 2008)

I'm looking for a digital tds meter myself. Which brand is good?


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## ohbaby714 (Feb 23, 2011)

http://www.amazon.com/gp/aw/d/B002C0A7ZY/ref=mp_s_a_1?qid=1315435279&sr=8-1

Been using this, for about a month now. Pretty decent. Plus really cheap from Amazon


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## Kazuya (Apr 4, 2011)

Has anyone used the TDS meter in op?


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## mordalphus (Jun 23, 2010)

I use the ones in the OP, works good


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## jkan0228 (Feb 6, 2011)

Sorry to ask what it's a simple question. What is TDS?


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## Kazuya (Apr 4, 2011)

Total dissolved solids


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## GeToChKn (Apr 15, 2011)

mordalphus said:


> I use the ones in the OP, works good


Does it come with a calibration source liquid? Do I need to buy a meter with one or can you easily make your own?


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## Jeffww (Aug 6, 2010)

Kazuya said:


> Total dissolved solids


More precisely: The sum of almost all ions, organic molecules and floating particles in your water in ppm. It's really a shot gun measurement that imo isn't very useful.


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## shrimpnmoss (Apr 8, 2011)

Jeffww said:


> More precisely: The sum of almost all ions, organic molecules and floating particles in your water in ppm. It's really a shot gun measurement that imo isn't very useful.


All ions that conduct electricity. It's useful if you start with pure RO and know exactly what you are putting in.


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## jkan0228 (Feb 6, 2011)

Looks like I need one for my shrimp tank....


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## zdnet (Aug 13, 2010)

Jeffww said:


> More precisely: The sum of almost all ions, organic molecules and floating particles in your water in ppm. It's really a shot gun measurement that imo isn't very useful.


Do you know of anything more useful on indicating water purity?


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## OverStocked (May 26, 2007)

Jeffww said:


> More precisely: The sum of almost all ions, organic molecules and floating particles in your water in ppm. It's really a shot gun measurement that imo isn't very useful.


I think it is a more useful measurement than pH, Kh, or GH. It is a farely good indication of the cleanliness of your tank. Particularly if you know your starting point. 

It is a good measurement for shrimp too.


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## jkan0228 (Feb 6, 2011)

So it is possible to have low kh and gh but high TDS? Or are those somehow intertwined?


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## ohbaby714 (Feb 23, 2011)

GeToChKn said:


> Does it come with a calibration source liquid? Do I need to buy a meter with one or can you easily make your own?


This one have a calibrated potentiometer in the back with label "Calibrate with NaCl".
I'm sure you can get calibration solution online and just adjust the pot in the back. For $17, it do not come with the solution.


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## happi (Dec 18, 2009)

jkan0228 said:


> So it is possible to have low kh and gh but high TDS? Or are those somehow intertwined?


yes was the answer i was given in previous post. since my test kits also given this answer in my post.


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## jkan0228 (Feb 6, 2011)

Is there a calculator similar to the ppm to degree conversion of kh and gh?


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## happi (Dec 18, 2009)

mordalphus said:


> Yes, tds could be "cleanliness", ro water has close to zero solids disolved in it. Water with nitrates and phosphorus has more solids dissolved.
> 
> Reconstituted ro water measured with a tds meter will yield a ppm of hardness, only because you have only the hardener dissolved into the water


good answer, i agree with you, i can start with 87 tds in my tank and it will make its way up to 150 within next day if measured by tds meter. i do add the EI dosing on top of that.


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## happi (Dec 18, 2009)

jkan0228 said:


> Is there a calculator similar to the ppm to degree conversion of kh and gh?


http://www.csgnetwork.com/directhwppmcvt.html

KH and GH are measured in same numbers, 1dgh is 17ppm of either one.

Note: calc is little bit wrong, am sure you will find out when you use it, other than that it work fine.


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## jkan0228 (Feb 6, 2011)

happi said:


> http://www.csgnetwork.com/directhwppmcvt.html
> 
> KH and GH are measured in same numbers, 1dgh is 17ppm of either one.


Yea I know but is there a calculator for TDS?


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## happi (Dec 18, 2009)

jkan0228 said:


> Yea I know but is there a calculator for TDS?


TDS can change from time to time and i dont think there is any calc for it. 

my tank water read .5KH and 5GH 5x17= 85tds and the tds increases by it self or after dosing some ferts but 5Gh remain the same or become 6Gh if am dosing Ca and Mg, right now tds is reading 200ppm+ with the meter but API reads 6dgh


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## MsNemoShrimp (Apr 25, 2011)

Looks like this stuff needs calibration liquid, similar to drop checkers almost? Could one use table salt w.o iodine to calibrate then?

ohbaby714, how did you calibrate yours?


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## ohbaby714 (Feb 23, 2011)

NeoShrimp said:


> Looks like this stuff needs calibration liquid, similar to drop checkers almost? Could one use table salt w.o iodine to calibrate then?
> 
> ohbaby714, how did you calibrate yours?


I had never calibrate mine yet. It came calibrated, but i'm sure it not perfect. Anyway, i use rain water and it measure 5-10ppm. That's usually better than my ro machine can make. I figure in about 6 month or so, i'll get some NaCl and calibrate it.


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## BradH (May 15, 2008)

happi said:


> http://www.csgnetwork.com/directhwppmcvt.html
> 
> KH and GH are measured in same numbers, 1dgh is 17ppm of either one.
> 
> Note: calc is little bit wrong, am sure you will find out when you use it, other than that it work fine.


I might be wrong, but I think it's 17.9 instead of just 17.


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## mordalphus (Jun 23, 2010)

You don't need to calibrate most of these meters. I've been using one for 6 months and it's still spot on with no calibration.

At this rate I would be satisfied if I burned through one every few months, however the ones I have keep on tickin.

It's up to you, these are so easy to use it's ridiculous, you just turn it on, dip it in the water, and it shows you within a millisecond what the TDS of your water is. Those strips are so inaccurate that they only show to the nearest 50, 70, 50, 80, 175 AND you have to use your eyeballs to judge which shade of BROWN it is... how ridiculous is that. With these, you can test every day 5 times a day for 6 months and it tells you in exact parts per million what your TDS is.

At the very least, get an API liquid GH and KH test kit. They're more useful than a TDS meter, but expire faster and are more difficult to use, but they tell you your GH and KH.
I use mine in conjunction with my TDS meter to figure out how much extra "junk" is in my water. IE. if my GH is 5 and my kh is 0, i know i have roughly 90 ppm of hardness, the rest of the ppm is nitrates, other minerals (such as aluminum, selenium, zinc, etc since I have a mineral stone), and other biproducts from plants and animals. So I know that with my mineral rocks and my GH of 5, my "clean" water is a TDS of 180, when it gets to 200, I know I have enough nitrates and other gunk in the water that I need a water change, which will lower it back down to 180 TDS.

It's not a massive advantage for the hobby shrimpkeeper, but it lets me know at a glance how clean my water is and roughly how hard my water is.

Also, if you're using ANY tap water in your tank, it'll tell you exactly how clean your tap water is (which for most folks is downright disgusting 350 ppm of TDS is average).


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## happi (Dec 18, 2009)

BradH said:


> I might be wrong, but I think it's 17.9 instead of just 17.


you are correct, but i did not bother writing that extra .9


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## jkan0228 (Feb 6, 2011)

What I find hard about the API test kits is that it says when it turns blue to yellow or red to green. Sometimes I get green or yellow after the first few drops but at a very light color. No blue or red...

Liam, you just made me wanna get one of those meters...


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## mordalphus (Jun 23, 2010)

lol, well that wasn't my intention, but if you want one, there are really cheap ones from hong kong on [Ebay Link Removed] I have a bunch I bought earlier this year in february, but they wouldn't be as cheap as the ones straight from hong kong.


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## jkan0228 (Feb 6, 2011)

Haha nothing here is as cheap when it's straight from Asia.... 
And from what I've read, a good TDS is 150-180? CRS that is.


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## mordalphus (Jun 23, 2010)

yeah, 150-200 is good. adjust your water to 5 GH, 0-1KH, then take a reading. If you have a mineral stone in your tank, it'll raise the TDS by another amount, but wont raise the GH or KH any. That is my baseline. For new water during water changes, I add mosura mineral plus til it hits 150 TDS, then put it in my tank. Once it's in my tank, my mineral rocks add about 30 TDS, so it reaches 180 in a tank of clean water. once it raises to 200-220, I do a water change and it will drop back down to 180.


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## zdnet (Aug 13, 2010)

jkan0228 said:


> What I find hard about the API test kits is that it says when it turns blue to yellow or red to green. Sometimes I get green or yellow after the first few drops but at a very light color. No blue or red...


I found it very difficult to detect the API GH color change. Much easier with Nutrafin.


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## jkan0228 (Feb 6, 2011)

Ok I think I'll PM you since its getting off topic :tongue:


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## bsk (Aug 18, 2010)

I just picked one up and found out my 60p is 460 ppm wow! I'm surprised my shrimp crs are still alive. I was so shocked I just ordered an RO unit. My tap is running about 260 ppm. that cheap $20 tds meter was the best thing I've bought for my little shrimpys.


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## GDP (Mar 12, 2011)

bsk said:


> I just picked one up and found out my 60p is 460 ppm wow! I'm surprised my shrimp crs are still alive. I was so shocked I just ordered an RO unit. My tap is running about 260 ppm. that cheap $20 tds meter was the best thing I've bought for my little shrimpys.


Yeah I love mine for nothing else other then peace of mind. I also dont check GH/KH as often. Luckily last time I checked my tap water is about 180TDS. But I live in NC which is very swampy so its natrually acidic and low tds.


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## johnny313 (Apr 15, 2011)

does TDS really matter? if you do water changes with 50%- 50% RO/tap monthly, and shrimp are alive and breeding.


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## GDP (Mar 12, 2011)

johnny313 said:


> does TDS really matter? if you do water changes with 50%- 50% RO/tap monthly, and shrimp are alive and breeding.


 
It depends. If that TDS reading is something negitive in your tank like copper or what have you then yes it matters. If its just high GH/KH then it depends on what youre keeping. I know my GH out of tap is 4GH. My KH is 1-2. According to that I think my TDS should be around 90 or so if my water was pure. But its a TDS of 180ish so that tells me there is other trace elements or whatever.

Like anything else its just a tool. To properly use a tool you need knowledge and expirence.


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## BradH (May 15, 2008)

I ordered one. I have really never thought about it before, but I think it will come in handy. For example. You could do a huge almost 100% water change, or if you setting up a new tank, then test your tds. Then after you dose your ferts you could test again. Then in a few days, week, ect. you could test and get an idea to help you on dosing, unless your doing EI or something. Which still could be helpful. Plus it could help you as said in knowing when to change the water. Maybe you need to change more often than you thought or maybe your changing your water for nothing sometimes. Not nothing because I clean water is good, but maybe you could stretch it out a little longer sometimes when you thought you couldn't.


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## Jeffww (Aug 6, 2010)

GDP said:


> It depends. If that TDS reading is something negitive in your tank like copper or what have you then yes it matters. If its just high GH/KH then it depends on what youre keeping. I know my GH out of tap is 4GH. My KH is 1-2. According to that I think my TDS should be around 90 or so if my water was pure. But its a TDS of 180ish so that tells me there is other trace elements or whatever.
> 
> Like anything else its just a tool. To properly use a tool you need knowledge and expirence.



The issue is that you can absolutely not know what the contributing to the TDS. It's taking the sum of practically EVERYTHING in the water not just metals. That is why I believe it's a reading that doesn't need to be taken unless you think your RO filter needs replacing. I love how people on this forum say other tests are unecessary but one that's even more imprecise/general is like a god send to the hobby. 

Again. I don't believe that a TDS meter is necessary for good fish/shrimp keeping regardless of what happens. Most keepers of shrimp/fish are going to be making at minimum monthly water changes anyways so what's the point?


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## zdnet (Aug 13, 2010)

Jeffww said:


> Again. I don't believe that a TDS meter is necessary for good fish/shrimp keeping regardless of what happens. Most keepers of shrimp/fish are going to be making at minimum monthly water changes anyways so what's the point?


A TDS meter helps to avoid unnecessary water change. It therefore reduces the waste of fresh water - a limited natural resource.


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## MsNemoShrimp (Apr 25, 2011)

zdnet said:


> A TDS meter helps to avoid unnecessary water change. It therefore reduces the waste of fresh water - a limited natural resource.


I totally agree on that. Dumping 20-25% on water changes is quite a bit. Especially when some do it as often as every week. I try to do it bi-weekly to avoid that and with the TDS, I might even go for a month if its possible.

GO GREEN! :biggrin:


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## zdnet (Aug 13, 2010)

NeoShrimp said:


> I try to do it bi-weekly to avoid that and with the TDS, I might even go for a month if its possible.


Depending on the tank set-up, you may be able to go even much longer before the next water change.


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## jkan0228 (Feb 6, 2011)

Basically when your TDS gets too high, 180+, just do a WC?


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## MsNemoShrimp (Apr 25, 2011)

zdnet said:


> Depending on the tank set-up, you may be able to go even much longer before the next water change.


Thats actually very good to know. Even better! So from Liam's recommendation, I'll just only do water changes when it gets anywhere past 180ppm.


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## mordalphus (Jun 23, 2010)

My baseline "clean" tds is 180, I do a wc when it gets up past 200. You need to figure out what your clean tds is first.


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## jkan0228 (Feb 6, 2011)

Its basically calculating percentage of your water change to reach your target TDS right? 
What do you people aim for after a water change, 180? or say 170?


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## mordalphus (Jun 23, 2010)

I aim for 180 because that's what my water is with just minerals and mineral rock in it. I think if you're not using mineral rock, your clean water would be around 150-160, but that's just speculation on my part. Do a big water change with water that's adjusted to 4-5 GH and 0-1 KH and test the water in your tank. That should be your target number


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## MsNemoShrimp (Apr 25, 2011)

mordalphus said:


> I aim for 180 because that's what my water is with just minerals and mineral rock in it. I think if you're not using mineral rock, your clean water would be around 150-160, but that's just speculation on my part. Do a big water change with water that's adjusted to 4-5 GH and 0-1 KH and test the water in your tank. That should be your target number


Thanks for all this valuable info :biggrin:
Btw, which brand of mineral rocks do you use? I heard they don't really work?


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## zdnet (Aug 13, 2010)

NeoShrimp said:


> So from Liam's recommendation, I'll just only do water changes when it gets anywhere past 180ppm.


I do not think there is a TDS number that applies to all tanks. You may want to establish your own. One way is doing a typical water change and taking a TDS reading afterward. That gives you a baseline TDS for the tank. Then take a TDS reading at the same time and spot each day for the following 7 days. The daily readings will tell you how your daily maintenance (including feeding) affects water quality. If the daily readings suggest that a weekly water change is not needed, you may switch to taking TDS readings at a longer interval, say weekly, monthly, etc.

BTW, you may be surprised at how infrequent a water change is really needed. Here is what Diana Walstad said in her book "Ecology of the Planted Aquarium":

"For example, my own aquariums often go for six months or more without water changes. Fish get fed well, so that plants do not need to be fertilized artificially. The only routine maintenance is replacing evaporated water and pruning excess plant growth. Tanks that are unbalanced need constant cleaning and adjustment."

Maintaining a balanced tank requires that we understand the impact of what we had done. Thus, a TDS meter is invaluable - it quickly tells us how our past actions had impacted the water quality.


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## GDP (Mar 12, 2011)

Jeffww said:


> The issue is that you can absolutely not know what the contributing to the TDS. It's taking the sum of practically EVERYTHING in the water not just metals. That is why I believe it's a reading that doesn't need to be taken unless you think your RO filter needs replacing. I love how people on this forum say other tests are unecessary but one that's even more imprecise/general is like a god send to the hobby.
> 
> Again. I don't believe that a TDS meter is necessary for good fish/shrimp keeping regardless of what happens. Most keepers of shrimp/fish are going to be making at minimum monthly water changes anyways so what's the point?


I already stated that a TDS meter will not tell you everything that in the water. If you dont think a TDS meter is needed thats fine. But I dont perticularly care. IT works for me and many others because we know what should or is already in our water. I KNOW what my GH and KH is, so I know when its time to change water water based on TDS.


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## MsNemoShrimp (Apr 25, 2011)

Which brand of mineral rocks are used by breeders here? How does that change the TDS reading and is it really necessary?


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## MsNemoShrimp (Apr 25, 2011)

My TDS meter just arrived today. My bf won a bid on for it for under $6 : ) 
(I didn't know he would bid on it as soon as I told him about it. Lol)

Anyways, as soon as he put it in my CRS holding tank, it read 340ish. Yikes! That is almost double what people are telling me to keep CRS in. "Around 150-200 TDS only for successful CRS keeping and breeding." 

*How should we go on about reducing this, are water changes the only option. Would adding more Purigen & Activated Carbon/Ammonia Neutralizing Blend help?*


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## OverStocked (May 26, 2007)

NeoShrimp said:


> My TDS meter just arrived today. My bf won a bid on for it for under $6 : )
> (I didn't know he would bid on it as soon as I told him about it. Lol)
> 
> Anyways, as soon as he put it in my CRS holding tank, it read 380ish. Yikes! That is almost double what people are telling me to keep CRS in. "Around 150-200 TDS only for successful CRS keeping and breeding."
> ...


Water changes. What I the Tds I your water change? 

Purigen and carbon will do nothing.


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## shrimpnmoss (Apr 8, 2011)

Contrary to popular belief CRS can survive and breed in a variety of water hardness as long as your shrimps are used to it. I'm pretty sure they might do better in the recommended range of 100 - 200. BUT...I recently got 3 SSS+ Crowns from a successful breeder that keeps his shrimps 100% Asian Style....we're talking no water changes....ever....his CRS babies came in water that was 550ppm....:icon_eek:

I dropped them into my 170ppm water...no acclimation...no deaths...


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## GeToChKn (Apr 15, 2011)

shrimpnmoss said:


> Contrary to popular belief CRS can survive and breed in a variety of water hardness as long as your shrimps are used to it. I'm pretty sure they might do better in the recommended range of 100 - 200. BUT...I recently got 3 SSS+ Crowns from a successful breeder that keeps his shrimps 100% Asian Style....we're talking no water changes....ever....his CRS babies came in water that was 550ppm....:icon_eek:
> 
> I dropped them into my 170ppm water...no acclimation...no deaths...


Yup, they can pretty resilient. I was taking out some plants I had in a planted and threw them all in a plastic shoe tote with some water from another tank. 5 days later the wife is poking through the tote and sees one of my higher grade CBS hanging out in the bottom. No airstone, no food, just a wack of bunches of all kinds of plants from 3 tanks. It was fine. Few weeks ago, I got the smart idea to add some barley pellets to suck up some nitrate in my crystal tank and they worked for some else, I thought, why not put them in my Rena. Instant coffee water, so I did a big WC, had no RO, was all tap, screwed my pH of netlea soil controlled water. pH went from 6.2 to 7.4. They did fine. Then it was lots of RO water changes to get the soil to kick back in, way less TDS on them. They've been through hell lately, got probably 20 babies right now, 2 gens going, and saw some doing the happy dance last night.

They can take a lot and I think if you baby them too much, they become weak. lol. Like a mama's boy shrimp. Sensitive to everything.


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## BradH (May 15, 2008)

I just received my tds meter in the mail. I was actually surprised how high it was in my 10 gallon tank.


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## MsNemoShrimp (Apr 25, 2011)

BradH said:


> I just received my tds meter in the mail. I was actually surprised how high it was in my 10 gallon tank.


Thats nice to know. Where did you get it? So is your TDS?


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## RandomMan (May 31, 2011)

Also, once the water is in your tank TDS is no longer an accurate way to measure hardness. 

A TDS meter is a great shortcut to measure hardness when you are starting with RO water, and adding minerals back into the water. Because you know the TDS meter is reading the minerals you've put in.

Once it goes into the tank there's other stuff that can dissolve in the water that will raise TDS, but have no effect on hardness.


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## BradH (May 15, 2008)

NeoShrimp said:


> Thats nice to know. Where did you get it? So is your TDS?


I got it off [Ebay Link Removed] My tap is 118, but the tap I drink is 92. It's water out of the fridge, has a small filter on it. The tds in my heavily stocked 29 gallon is 178 and the tds in my 10 gallon shrimp tank is 192. lol I was expecting the tds in the shrimp tank to be alot lower. I've had problems though with hardness in this tank.


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## MsNemoShrimp (Apr 25, 2011)

RandomMan said:


> Also, once the water is in your tank TDS is no longer an accurate way to measure hardness.
> 
> A TDS meter is a great shortcut to measure hardness when you are starting with RO water, and adding minerals back into the water. Because you know the TDS meter is reading the minerals you've put in.
> 
> Once it goes into the tank there's other stuff that can dissolve in the water that will raise TDS, but have no effect on hardness.


I am a little confused here, can't you measure hardiness on its own and TDS on its own once the tank is filled? For example, our emersed tank right now, the TDS is 350ish with the little water that is in there that we test. Our RO water is 15ish. Once we fill up the tank all the way, we can't expect it to be that low still even though its 95% of the TDS 15 water.



BradH said:


> I got it off [Ebay Link Removed] My tap is 118, but the tap I drink is 92. It's water out of the fridge, has a small filter on it. The tds in my heavily stocked 29 gallon is 178 and the tds in my 10 gallon shrimp tank is 192. lol I was expecting the tds in the shrimp tank to be alot lower. I've had problems though with hardness in this tank.


Our tap is way higher. At 285! Ewww!

So if later on we do water chages at 50/50 tap and RO, that's going to come out to 150ish TDS already going into the tank, which is perhaps too high even for water changes.We should do 25% tap and 75% RO since our tap water is higher than most places I would assume?


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## mordalphus (Jun 23, 2010)

you can measure hardness with your GH and KH test kits once it's in your tank, but using TDS alone to measure hardness in your tank is not a good indicator since things like nitrates, phosphate, potassium, etc will be included in the TDS. These things aren't present in RO water, so when you are adding your mineral additive to the RO water, the TDS will be of hardness only.

However, if you first start a tank with 150 TDS water, and within a few weeks of not doing water changes, the water is now 200 TDS but the GH and KH are the same, you know that there's 50 PPM of other stuff in the tank such as nitrates, phosphate, etc. and you simply remove a few gallons, and replace with 150 TDS water.

Using a tap/RO mix is not a good way to get your TDS in the right spot. There are a lot of things in tap water that affect TDS that don't affect the hardness. Just because your tap water is 285 TDS, doesn't mean it's 10 GH. It could be 0 GH but 285 ppm of copper and lead. That is why mineral additives exist


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## RandomMan (May 31, 2011)

NeoShrimp said:


> I am a little confused here, can't you measure hardiness on its own and TDS on its own once the tank is filled?


Most people are using TDS as a proxy for hardness. Its a lot easier to dip a TDS meter in water and push a button than it is to do your normal GH/KH tests with tubes and drops.

So you take your RODI water which has a TDS of 0 (or whatever), add minerals back in, measure until you've got 150, or 180 or whatever target TDS is. You aren't really shooting for TDS, you're using TDS as a proxy for hardness. You'll see some people add a KH booster until it hits 100, then a GH booster until TDS reach whatever the target amount is. Because you know what you are adding into the water, and you know the starting TDS, you can easily estimate the effect on hardness.

Once the water is in your tank, you have other things that are disolving in the water that will affect your TDS. However, you won't know what is causing the change in TDS and what affect they'll have on your water parameters. At this point, TDS can no longer function as a proxy for water hardness. It now is just "total dissolved solids" which can be just about anything. Some may be bad for your shrimp, some may have no effect. You don't know.

Here's a more detailed explanation of how the TDS meter works:
http://www.reefkeeping.com/issues/2004-04/rhf/feature/


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## MsNemoShrimp (Apr 25, 2011)

From what I can understand from the last two posts is that TDS is measured BEFORE adding into the tank using RO or DI water is that correct? Which means, do whatever you need to do prior to adding that water into the tank?

So in my case, for easier understanding, some of the water that is left in the emersed growth of my tank reads out 350ppm. Obviously that includes all the possible particles listed above. There is about 5% of that water in the emersed setup.

A.) Should I use a pipette to suck it all out to replace all that 5% with new 20ppm RO water to decrease the initial TDS reading already in the tank?

B.) The tank will be filled at the end of this month, so how should I prepare the RO water I will be using to fill it up with? With the current 20ppm reading, I should add "minerals" to get it up to 150ppm before adding it in such as Liquid potassium, iron, excel, stuff like that?


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## GDP (Mar 12, 2011)

NeoShrimp said:


> From what I can understand from the last two posts is that TDS is measured BEFORE adding into the tank using RO or DI water is that correct? Which means, do whatever you need to do prior to adding that water into the tank?
> 
> So in my case, for easier understanding, some of the water that is left in the emersed growth of my tank reads out 350ppm. Obviously that includes all the possible particles listed above. There is about 5% of that water in the emersed setup.
> 
> ...


 
The only way for sure to know what your TDS reading actually is, is to know what your GH and KH really is. That and use distilled water. If you were to remineralize DI water to the proper GH/KH and TDS reads say 80 PPM, you know that is what your clean water tds is. As mord stated.

Then once you add that to your tank it may go up depending on nitrites, phospherous, ect. Take TDS reading again a week after doing this, and that is your normal clean water TDS. Because there shouldnt be anything in there other then ferts/nitrates/hardness.

From then on you can soley rely on the TDS meter for the most part because you know what your baseline readings are. Basically ive just restated what mord. has been saying but hopefully in a way most people can comprehend.


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## MsNemoShrimp (Apr 25, 2011)

GDP (I need to get your name), thank you for that wonderful clarification. RandomMan (I also need your name) and Liam, very useful as well no doubt. 

In short, I understand what you guys are trying to tell me now : )

A.) Prior to filling my tank, pipette all the water out that is still remaining in the tank for emersed growth. The reason being...350ppm TDS reading is a bit scary to me.

B.) For my RO water (all 12 gallon of it that I want to fill the tank with) "remineralize" it to get it to a proper GH/KH that I want and measure that TDS alone.

My goal for GH and KH for CRS would be in the range of 2-5.

C.) Once I get the TDS reading of the remineralized RO water, fill my tank with it. Get the TDS reading when I am done filling the tank and a few more times throughout the week (just to keep track), and by the end of the week, my TDS reading will meansure my "clean water" TDS, my baseline.

D.) With my baseline TDS in mind, if it goes 50+ppm over, then it means that its time for a water change.

*Please correct me if any of these steps are wrong. Also, is my goal GH/KH right for CRS and lastly, what do I use to "reminaralize" to get my GH/KH to the proper level, just tap water?*


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## GDP (Mar 12, 2011)

NeoShrimp said:


> GDP (I need to get your name), thank you for that wonderful clarification. RandomMan (I also need your name) and Liam, very useful as well no doubt.
> 
> In short, I understand what you guys are trying to tell me now : )
> 
> ...


Honestly im not sure what DI water + the right amount of GH and KH equal out to in terms of TDS numbers. I need to do it myself lol.


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## MsNemoShrimp (Apr 25, 2011)

GDP said:


> Honestly im not sure what DI water + the right amount of GH and KH equal out to in terms of TDS numbers. I need to do it myself lol.


By the end of this month, I have to get the water prepared and that is when I would be able to compare results with you : ) Is there much difference between using RO water or DI water? And what do you use to remineralize the water?


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## sampster5000 (Oct 30, 2010)

In relation to the thread...

Dow Jones Industrial Average fell 3.51 points. TDS meters are up 5 points.


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## GDP (Mar 12, 2011)

NeoShrimp said:


> By the end of this month, I have to get the water prepared and that is when I would be able to compare results with you : ) Is there much difference between using RO water or DI water? And what do you use to remineralize the water?


DI (Distilled) water is 0 TDS. Its absolutely 100% pure h20. RO (Reverse Osmosis) water is I believe about 20-80 TDS and shouldnt have anything other then some hardness.


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## OverStocked (May 26, 2007)

GDP said:


> DI (Distilled) water is 0 TDS. Its absolutely 100% pure h20. RO (Reverse Osmosis) water is I believe about 20-80 TDS and shouldnt have anything other then some hardness.


Di is deionized


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## MsNemoShrimp (Apr 25, 2011)

0 TDS for DI and not RO? I guess some online info is false then because some people say you can get 0 TDS from RO water if the system is good enough. I think it would be possible but it would also mean lots of $$$. My RO is reading different numbers. Between 16 - 20. That should be good enough since you have to remineralize them anyways.

I got my Fluval Shrimp Mineral Supplements from Brandon today. Looks like really good stuff. I will have my bf work on adding this to our 5G jug tonight or tomorrow when he has time. What should be our "goal" TDS? 

Lets say currently the RO water in the 5G jug is measuring out 20 TDS, the next step is add enough solution to it to get it around 80-100 from what I recall?


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## mordalphus (Jun 23, 2010)

It depends on how how much TDS is 5 GH when you use fluval minerals... With mosura mineral plus, it's around 150 TDS (even though the TDS->GH conversion is a different reading, mineral additives have minerals OTHER than calcium).

To find out, you'd have to measure 5 GH in fluval minerals, then take a TDS reading. That would be the TDS you'd raise it to every time after that.

The directions on the bottle are for a 20 gallon tank. I think it says it raises 20 gallons by 1 GH by adding 5 ml of liquid.

So for 5 gallons, 5 ml would raise it about 4 GH, which is fine too. So add 5 ml to your 5 gallons of RO, test the TDS, and that is your tds that you adjust to every time you make new water.


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## MsNemoShrimp (Apr 25, 2011)

Just recently did the test w/ my bf. With Fluval Shrimp Mineral Supplements @ kH of 0-1 and gH of around 5 - 6, TDS reads 170.

This is coming from a 100% RO 5 gallon water jug, @ TDS of 18, kH/gH of 0-1, and then adding 9ml of Fluval Shrimp Mineral Supplements to it.

Sounds right enough?


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## Betta Maniac (Dec 3, 2010)

Ok, so you all got me thinking about my gH and kH ... out of the tap, both tests (Nutrafin) turn the final color on the first drop. Apparently I have RO water flowing out of the tap (and yes, I tested the tanks I use SeaChem Equilibrium in to make sure the tests were working). 

When I test the shrimp tank, the gH takes 4 drops to change and the kH still changes on the first drop. So I think I'm good shape. Right? I ordered one of the mineral stones from Liam cause my water is so soft it I thought it might be good for them.


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## mordalphus (Jun 23, 2010)

Yah, most people on the west coast (norcal, Oregon, Washington) have super soft water out of the tap. 4 Gh is fine, 0 kh fine too. The mineral stone won't raise the Gh by much, maybe half a degree, but it let's the shrimp have a source to go to if they need


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## jkan0228 (Feb 6, 2011)

mordalphus said:


> It depends on how how much TDS is 5 GH when you use fluval minerals... With mosura mineral plus, it's around 150 TDS (even though the TDS->GH conversion is a different reading, mineral additives have minerals OTHER than calcium).
> 
> To find out, you'd have to measure 5 GH in fluval minerals, then take a TDS reading. That would be the TDS you'd raise it to every time after that.
> 
> ...


I forgot if I asked you or not. But in a 11g I would add about 15ml to raise the gh to 6 right?


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## GeToChKn (Apr 15, 2011)

jkan0228 said:


> I forgot if I asked you or not. But in a 11g I would add about 15ml to raise the gh to 6 right?


Here is the thread where it was calculated to show how much to use.

http://www.plantedtank.net/forums/s...al-shrimp-mineral-supplement.html#post1371643

So going by that, 1.875ml should get 1 gallon of RO water to to gH 4-5. I would say round off to 2ml per gallon of pure RO water for a good crystal average. That's going by those calculations and I guess I will try and verify with a test later or someone else. I am waiting on TDS meter too so I can't test that right now but neo's findings seem to be spot on.


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## MsNemoShrimp (Apr 25, 2011)

mordalphus said:


> Yah, most people on the west coast (norcal, Oregon, Washington) have super soft water out of the tap. 4 Gh is fine, 0 kh fine too. The mineral stone won't raise the Gh by much, maybe half a degree, but it let's the shrimp have a source to go to if they need


Liam, how can you get a measurement of 0? When I add a drop that is when I find out but unsure how to test the "zero".



GeToChKn said:


> Here is the thread where it was calculated to show how much to use.
> 
> http://www.plantedtank.net/forums/s...al-shrimp-mineral-supplement.html#post1371643
> 
> So going by that, 1.875ml should get 1 gallon of RO water to to gH 4-5. I would say round off to 2ml per gallon of pure RO water for a good crystal average. That's going by those calculations and I guess I will try and verify with a test later or someone else. I am waiting on TDS meter too so I can't test that right now but neo's findings seem to be spot on.


I was hoping to get a rough idea of what the "clean" TDS should be just straight from adding supplements to the pure RO or DI water. Mine reads 170ish for gH of around 5 and kH of 0 or 1, have not gotten a TDS reading with it filled in our 12G tank yet but that will come shortly. Unfortunately our flooding date will be delayed until tomorrow. October 1st will be our day : )

Will take pics and upload to share with everyone in my first Planted Tank journal :bounce:


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## mordalphus (Jun 23, 2010)

To test for 0, simply double up the amount of water you're testing. If you test 10ml with the drops and it changes right away, it would mean it's .5 KH or less, at that point it's safe to say it's at or near zero.


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## pomby27 (Jan 27, 2004)

slightly off topic, neo did you go to erc? haha


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## londonloco (Aug 25, 2005)

I've been watching this thread since it's start. I have well water, I knew my TDS was really high out of the tap, but still, stupidly, tried to keep yellow and red cherry shrimp for over two years. I wasted more $$ on shrimp. I finally broke down and bought a Hanna meter. Out of tap, my TDS is over 500. Depending on the tank, after a week, it goes up to 600-700. I tested my daughters city water, TDS is 180 out of tap, after a week in a 5g soil capped with black Flourite planted tank, no dosing, it reads 220ish. Yesterday I added 10 red cherry shrimp to the tank, babies, from Rachel. All 10 are happily swimming in the tank this morning. I've never had such an active shrimp tank. I'm pretty happy


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## 150EH (Dec 6, 2004)

I've been reading along as well, I've been having a problem with silicates which would only be part of the TDS in my water but I'm making the move to RO/DI unit even though we have a whole house softner that keeps my kH at 7 and gH 4 which is not too bad. But I've been battling poor water for 8 years or better from this tap, now I need to understand my water a little better, this link helped a little but I need to look deeper.

A good RO/DI retailer will also have some info, like http://www.bulkreefsupply.com/store/ has some videos that help you understand it a little better. I also noticed they give you a nice TDS meter with some of the better systems ($200) because it's important to know if your RO/DI unit is working properly, does it need to be back flushed or is it time to replace cartridges.

I also use a software program to track fish, plants, and changes in my tank it's called Aquarix but it also helps you mix your tap & RO water to get the gH/kH you want in your tank, I'm sure it can be done easily with a pencil too but this makes it easier.


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## 150EH (Dec 6, 2004)

Something to ponder, my little software program told me if I want a gH & kH of 3 each lets say for kicks on a 62.5 gallon water change (my shrimp tank is just bigger) I would need:
....................gH..........kH
tap water.......27.6.....18.16 gallons
RO/DI water....34.9.....44.34 gallons

So you can adjust for one with tap water but may need to add salts to raise the other. Although most won't need it to be dead on for both and would just use one or the other.


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## londonloco (Aug 25, 2005)

That's my problem, I'm not willing to go there. I can keep most fish, and most plants, so I go with what I can keep. My life is way to "active" to start mixing water. The fact I've got a 5g that I have to ship in water for is going way beyond what I have been willing to do in the past. Maybe someday, when the kids are gone, and my time is freed up. Until then, I'll keep this 5g tank, the other 7 tanks will have to deal with my well water.


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## wkndracer (Mar 14, 2009)

Jeffww said:


> The issue is that you can absolutely not know what the contributing to the TDS. It's taking the sum of practically EVERYTHING in the water not just metals. That is why I believe it's a reading that doesn't need to be taken unless you think your RO filter needs replacing. I love how people on this forum say other tests are unecessary but one that's even more imprecise/general is like a god send to the hobby.
> 
> Again. I don't believe that a TDS meter is necessary for good fish/shrimp keeping regardless of what happens. Most keepers of shrimp/fish are going to be making at minimum monthly water changes anyways so what's the point?


I have no problem with this post at all, none. Valid points made from a tankers point of view that doesn't use it. Many do indeed lose a piece of information here and there when learning from posts on the internet. (not the most accurate source LMAO) But the internet is convenient and so is a TDS pen. Used in conjunction with GH and KH tests that are at least zero calibrated then logging the results it does have a value to me. 

I don't have to have a pH controller to inject CO2 but I do and like using it.


RandomMan said:


> Also, once the water is in your tank TDS is no longer an accurate way to measure hardness.
> 
> A TDS meter is a great shortcut to measure hardness when you are starting with RO water, and adding minerals back into the water. Because you know the TDS meter is reading the minerals you've put in.
> 
> Once it goes into the tank there's other stuff that can dissolve in the water that will raise TDS, but have no effect on hardness.


Recording the baseline TDS reading after a water change I disagree with that being the end of TDS usefulness. Using RO and setting GH and KH values, testing NO3, PO4 I have known values for water quality. A month down the road after dosing, feeding fish, trimming plants yada yada The ratio between my recorded values has shifted by a significant amount. 

GH, KH, NO3 and PO4 tested at known values again and seeing an upward shift TDS 218 starting and 260 ending when other values stay well within range tells me my organics are going up


GDP said:


> DI (Distilled) water is 0 TDS. Its absolutely 100% pure h20. RO (Reverse Osmosis) water is I believe about 20-80 TDS and shouldn't have anything other then some hardness.


Using an 'off the rack' consumer grade 4 stage unit without the final stage DI polish I test at 2-3ppm product water with a good membrane regularly. 
:fish: 
Thread was a good read.


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## MsNemoShrimp (Apr 25, 2011)

Would it be safe to conclude that "clean" mineral RO/DI water TDS to be 170-200ppm? That is of course with 4-5 gH / 0-1 kH and a pH of 7, Ammonia & Nitrate of 0?


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## wkndracer (Mar 14, 2009)

NeoShrimp said:


> Would it be safe to conclude that "clean" mineral RO/DI water TDS to be 170-200ppm? That is of course with 4-5 gH / 0-1 kH and a pH of 7, Ammonia & Nitrate of 0?


5dgh, 1dKH only listed above should be 107 - 110ppm TDS
170 ppm would total in a combined range result of 9dH
200ppm combined range of 11dH

edit; Recorded the following in my log testing a tank.
9/21 TDS 137ppm, NO3 7ppm, 3dGH, 3dKH, PO4 0.25 (guessing slight color shift) and calculated Mg content of 13ppm.
The math total on the chemical tests is 127ppm. <,> 10ppm Factor guessing color shade errors and range error I'm happy with it.
Scanning back through my tank log after large water changes of 50 - 70% of tank volume the math always puts the pen within 20ppm of the math on chemical tests. 3 weeks or more beyond the change TDS results are skewed well above.

HTH


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## mordalphus (Jun 23, 2010)

That's if it was ONLY calcium in the water, however fluval shrimp minerals has other things too.


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## MsNemoShrimp (Apr 25, 2011)

mordalphus said:


> That's if it was ONLY calcium in the water, however fluval shrimp minerals has other things too.


Thanks for the clarification Liam. I tested it 4 times already with the starting 17ppm RO water. After the addition of the fluval shrimp minerals, it reads 4-5 gH, 0-1 gK and TDS reads out 170-180ppm.


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## MsNemoShrimp (Apr 25, 2011)

I would like to conclude that for Fluval Shrimp Minerals, TDS for 4-5 gH & 0-1 gK is 170-180ppm with 15-20ppm starting RO water : )


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## mordalphus (Jun 23, 2010)

Sounds about right. Same with mosura mineral plus. (if you started with 0, it would be about 150 at gh 4-5)


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## MsNemoShrimp (Apr 25, 2011)

Is it normal for TDS to go from mid 90's to near 120ppm in just a few days at random?


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## mordalphus (Jun 23, 2010)

What did you put in the tank?


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## MsNemoShrimp (Apr 25, 2011)

mordalphus said:


> What did you put in the tank?


When the 3ppm RO water was first added, the reading came out to 90ppm once the tank was filled, christmas moss tree added and everything else. The morning after it reads mid 90's and stayed that way for awhile. My bf just pulled up the christmas tree later last night out of the tank and since then till this morning it just rose to around 118/120ppm...


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## Cynth (Sep 11, 2010)

When I add Fluval Shrimp Minerals to my RO water @ 1ml per gallon the TDS is 103, the GH is 4 and the KH is 3.


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## zdnet (Aug 13, 2010)

NeoShrimp said:


> When the 3ppm RO water was first added, the reading came out to 90ppm once the tank was filled, christmas moss tree added and everything else. The morning after it reads mid 90's and stayed that way for awhile. My bf just pulled up the christmas tree later last night out of the tank and since then till this morning it just rose to around 118/120ppm...


Percentage-wise that is a 30% TDS jump overnight. My guess is that pulling out the "Christmas tree" the night before had released some densely packed nutrients from the newly set up substrate.


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## MsNemoShrimp (Apr 25, 2011)

zdnet said:


> Percentage-wise that is a 30% TDS jump overnight. My guess is that pulling out the "Christmas tree" the night before had released some densely packed nutrients from the newly set up substrate.


That makes perfect sense. Substrate is Fluval Shrimp + Eco-C and Osmocote + tabs at the far bottom. Overall, 120TDS reading in a somewhat established tank isn't too bad : )


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## youjettisonme (Dec 24, 2010)

My experience...

I was running an HOB on my CRS/CBS/blue rili tank. Basically, I would wait until the TDS rose above 200, do a 20% water change with RO/DI, and that would take it down to around 180. Eventually, I bought more filtration in the form of an Eheim Ecco that I run simultaneously in my 10 gallon with the AquaClear HOB. Now my TDS pretty much never rises above 180. I haven't done a water change in 6 weeks, but have only added to compensate for burnoff. Right now it's at 164. I use fluval mineral supplement with every top off, just a few drops at a time, to get my GH to 4-5. 

I use to have lots of unexplained deaths in this tank, but I haven't had any now in almost 2 months. Perhaps a lot of that has to do with no water changes, and therefore, less dramatic changes top the water. Plus, my water is just cleaner because of the Ecco.


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## MsNemoShrimp (Apr 25, 2011)

youjettisonme said:


> My experience...
> 
> I was running an HOB on my CRS/CBS/blue rili tank. Basically, I would wait until the TDS rose above 200, do a 20% water change with RO/DI, and that would take it down to around 180. Eventually, I bought more filtration in the form of an Eheim Ecco that I run simultaneously in my 10 gallon with the AquaClear HOB. Now my TDS pretty much never rises above 180. I haven't done a water change in 6 weeks, but have only added to compensate for burnoff. Right now it's at 164. I use fluval mineral supplement with every top off, just a few drops at a time, to get my GH to 4-5.
> 
> I use to have lots of unexplained deaths in this tank, but I haven't had any now in almost 2 months. Perhaps a lot of that has to do with no water changes, and therefore, less dramatic changes top the water. Plus, my water is just cleaner because of the Ecco.


Wow! That is just amazing. Thanks for sharing! When you say you add a few drops, is that just using a plastic pipette? And have you tried getting a TDS reading of the RO/DI you use after you added a few drops?


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## MsNemoShrimp (Apr 25, 2011)

zdnet said:


> Percentage-wise that is a 30% TDS jump overnight. My guess is that pulling out the "Christmas tree" the night before had released some densely packed nutrients from the newly set up substrate.


From a recent post that I've read, I believe another main cause are the Seriyu stones. People said it could increase your TDS by up to 100ppm every week depending how well the cleansing was prior to putting it in the tank. If that is the case + the removal of things lead to 30% increase in 5 days then that is not TOO bad...right?


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## zdnet (Aug 13, 2010)

NeoShrimp said:


> From a recent post that I've read, I believe another main cause are the Seriyu stones. People said it could increase your TDS by up to 100ppm every week depending how well the cleansing was prior to putting it in the tank. If that is the case + the removal of things lead to 30% increase in 5 days then that is not TOO bad...right?


That depends on the tank inhabitants. I would avoid it for crystal red shrimps - they require a very very stable environment.

However, we don't know how much of that 30% change was due to the one time event of pulling up the Christmas tree and how much was due to the Seriyu stones. I would hold off on changing any tank setting and get a TDS reading at the same tank spot and time everyday for several days. That should give a rough idea on the rate of change for the tank as it is now. If the rate is too high, remove the Seriyu stones and observe the impact.


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## matti2uude (Mar 4, 2009)

Before the summer I used to keep my Tds around 200 doing water changes with remineralized RO/DI water. I had hardly any baby crs survive. I stopped doing water changes and only top off with RO/DI water remineralized to 150 Tds. Since the change I have tons of babies surviving now but the Tds in my tank is at 700. Any explanation for this?


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## zdnet (Aug 13, 2010)

matti2uude said:


> Before the summer I used to keep my Tds around 200 doing water changes with remineralized RO/DI water. I had hardly any baby crs survive. I stopped doing water changes and only top off with RO/DI water remineralized to 150 Tds. Since the change I have tons of babies surviving now but the Tds in my tank is at 700. Any explanation for this?


I suspect if you measure the mineral concentration of the tank water, it will show a very high level. One possible explanation is that the tank water had been evaporated at a much faster rate than that of the mineral usage. Therefore, while the volume of a top-up was the same as that of the evaporated water, the mineral in the top-up water was much more than the mineral that had been used up. Consequently, the top-up increased the mineral concentration (and TDS) of the tank. When you repeated the top-ups, TDS climbed. 

To maintain a steady TDS, remineralize the top-up water _only_ when the tank water's mineral concentration is below the optimal level.


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## matti2uude (Mar 4, 2009)

Sorry I should've made my question more clear. 
How come my crs are doing way better with tons of babies at Tds 700 compared to when it was Tds 200?


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## zdnet (Aug 13, 2010)

I believe that is because stability is much more important than the actual value.


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## mordalphus (Jun 23, 2010)

Also, your 700 tds likely isn't hardness, it's likely mostly organic waste.

Are your babies growing at a normal rate? I'm guessing NOT, and that the babies stay small for a very long time. That would be caused from a buildup of waste.


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## jkan0228 (Feb 6, 2011)

What is the maximum TDS before you see reduced growth rate?


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## mordalphus (Jun 23, 2010)

That all depends on how much of your TDS is organic waste. I've noticed with a clean tds of 180, that my babies grow extremely slow at 230 tds. That's just me though. It's something I've witnessed recently when I tried keeping a tank without water changes. Compared to a tank where bi-weekly water changes were done, the babies in the no-change tank are still 3-5mm after 8 weeks, and the babies in the normal tank grew normally. The only difference in tanks being the TDS of the water, the GH, KH and pH are the same.


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## jkan0228 (Feb 6, 2011)

So about how big is a CRS at 8 weeks?


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## mordalphus (Jun 23, 2010)

Mine are 8mm to 1.2 cm by that age. Hard to keep track of age, but the tank that hasn't had a water change in it, babies are all under 1cm.


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## MsNemoShrimp (Apr 25, 2011)

mordalphus said:


> That all depends on how much of your TDS is organic waste. I've noticed with a clean tds of 180, that my babies grow extremely slow at 230 tds. That's just me though. It's something I've witnessed recently when I tried keeping a tank without water changes. Compared to a tank where bi-weekly water changes were done, the babies in the no-change tank are still 3-5mm after 8 weeks, and the babies in the normal tank grew normally. The only difference in tanks being the TDS of the water, the GH, KH and pH are the same.





mordalphus said:


> Mine are 8mm to 1.2 cm by that age. Hard to keep track of age, but the tank that hasn't had a water change in it, babies are all under 1cm.


Thanks for all this valuable information Liam. So when my CRS have babies in the future (crossing my fingers), I will make sure to change the water whenever the TDS reaches 220ppm.


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## MsNemoShrimp (Apr 25, 2011)

I want to bring up a topic that wasn't quite clear in this thread just so I can clarify.

*There is NO direct correlation between TDS w/ kH or gH correct?*

It seems to me that everyone who have a TDS of around 150-180ppm, their kH and gH values would be 0-1 & 4-5 respectively, but mine is more like 3-4 & 7-8 :icon_frow


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## Darth Toro (Mar 6, 2010)

I had a TDS of 150-180 with a gH of 2-3. I used the fluval shrimp mineral supplement to bring it up to 4 gH. Im still learning too. Just wanted to add my recent experience.


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## zdnet (Aug 13, 2010)

NeoShrimp said:


> I want to bring up a topic that wasn't quite clear in this thread just so I can clarify.
> 
> *There is NO direct correlation between TDS w/ kH or gH correct?*
> 
> It seems to me that everyone who have a TDS of around 150-180ppm, their kH and gH values would be 0-1 & 4-5 respectively, but mine is more like 3-4 & 7-8 :icon_frow


TDS measures water impurity. Among those things that affect impurity, only some of them affect kH or gH. Therefore, knowing the TDS alone, one cannot reliably tell the kH or gH.


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## mordalphus (Jun 23, 2010)

Correct, TDS is a total of all things dissolved into the water. IE, fertilizers, trace minerals and salts. That includes your GH and KH. If you were to test just GH and KH, they're 17.9 ppm per degree. So 179 GH and 0 KH would be 10 GH

So if you know your GH and KH, just multiply by 17.9.

So if you know your GH is 10, and KH is 0, and your TDS is 250, you know that only 180 TDS of that is GH, the other 70 TDS is other things in your water such as nitrates, potassium, phosphate, etc.


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## MsNemoShrimp (Apr 25, 2011)

mordalphus said:


> Correct, TDS is a total of all things dissolved into the water. IE, fertilizers, trace minerals and salts. That includes your GH and KH. If you were to test just GH and KH, they're 17.9 ppm per degree. So 179 GH and 0 KH would be 10 GH
> 
> So if you know your GH and KH, just multiply by 17.9.
> 
> So if you know your GH is 10, and KH is 0, and your TDS is 250, you know that only 180 TDS of that is GH, the other 70 TDS is other things in your water such as nitrates, potassium, phosphate, etc.


Thanks for the clarification Liam. I now have a firm grip on all this kH, gH and TDS...or so I think. Lol


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