# Is this a decent TDS Meter?



## natemcnutty (May 26, 2016)

Never used that one, but this is the one I use: https://www.amazon.com/gp/product/B001RK38LU/

The TDS-3 is your cheapest bet on there 

Thank @Oso Polar for this graphic


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## Wendy1B (Jan 8, 2017)

Thanks!


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## chappy6107 (Aug 2, 2016)

this is the one I use. tds meter works great.
https://www.amazon.com/gp/product/B017INK8QM/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1


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## newportjon (Mar 22, 2011)

I use the TDS-EZ on that chart. I've had it for several years, it still works and I love it.


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## Nordic (Nov 11, 2003)

Unless you regularly use and properly store these pen types of meters, their probes go funky.
Which is why I buy the cheap e-bay type pens. When the battery gets old, throw the pen away and get a new one.


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## roadmaster (Nov 5, 2009)

Forgive me,I am old and have always wondered what do most folks use TDS meter's for in freshwater aquaria?
Do they come with any information as to what all contributes to Total dissolved solid's in the aquarium?Fertilzer's,fish food's,fish poo,buffer's,substrate bacterial activity, decaying plant matter,basically anything capable of dissolving or going into solution will affect TDS.
Water change would be quickest way to reduce TDS as well as reducing that which contributes to TDS.
Do not believe any three tanks would test close to same for TDS unless they were empty of anything other than tap water or R/O water.
What say ??


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## Nordic (Nov 11, 2003)

It is of more importance to fishkeepers/breeders than botanists, I'd say. 
Low TDS is pretty important for the breeding of many Sout American fish.


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## roadmaster (Nov 5, 2009)

Yes,I agree.
But my thinking is once I determined what the TDS were by mid week, or end of week with all of the afore mentioned contributer's being present,(that I add directly? indirectly)then this might lead me to consider either feeding/stocking less or change more water.
I cannot see where TDS meter would be needed on regular basis once you know what you have by week's end and normal tank operation's,stocking,feeding's,fertilizer's,etc.
If one see's that the target TDS they wish for are achieved with say once weekly water change of 35 to 50 % ,then the meter would not seem as useful unless sudden changes are made to the system No?
I just do not believe that everyone is aware of just what all affect's TDS so maybe if they use it to induce water change (how else might you lower it? Trick question), then the TDS meter might serve them till they wise up.
Bout everything we add to ,or that which is produced in the aquarium as a result of that which was/is added ,affect's the TDS once in solution or dissolved.
Even tap water.


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## Nordic (Nov 11, 2003)

Exactly, you will find if we did a poll, that most members on here who own a TDS probe, has it somewhere in a drawer and have not used it for some time.
There are some people who use it to dose fertilizer as TDS can be used to determine concentrations. Once saw a very coherent explanation on here somewhere.

I think spending a tenner on a basic pen is worth it to get an understanding of the water supply you are working with, though.


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## nikohak (Oct 21, 2016)

Now if the probe goes out of calibration, will the error be constant or does it scale? 

By this I mean that we have a good steady tap water quality with low TDS, so can I just compare measurements between aquarium water and tap water and not worry about if the probe is calibrated or not?


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## Phokey (Oct 16, 2016)

I use the EC3 and find the hold feature to be useful since it doesn't have a backlight. I'm partial to Micro Siemens but here is a handy conversion tool in case you need it. 

https://www.easycalculation.com/unit-conversion/microsiemens-ppm-conversion.php

-Scott


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## jr125 (Mar 5, 2015)

Nordic said:


> Exactly, you will find if we did a poll, that most members on here who own a TDS probe, has it somewhere in a drawer and have not used it for some time.
> There are some people who use it to dose fertilizer as TDS can be used to determine concentrations. Once saw a very coherent explanation on here somewhere.
> 
> I think spending a tenner on a basic pen is worth it to get an understanding of the water supply you are working with, though.


I originally got a TDS meter when I got a RO unit for drinking water to monitor it's effectiveness over time. When my local water source started using chloramines it seemed there was also a significant jump in ph. I live outside the city and the rural water system uses the city water. From what I understand they really "juice" the water because of the length of time and distance the water is in the pipes to get to the far reaches of the system. Since I had the RO unit I started using that water for aquarium use as well.

I checked TDS in the aquarium occasionally mainly to see the effect of water changes and to see if I was getting any slow increase over time. TDS always stayed in a predictable range for the most part as long as I was regular with my maintenance.

When I started dosing the tank with dry potassium and a tiny bit of dry phosphate I checked a little more often to see the what effect that had on TDS. What I think I determined was that the potassium was building up over time and I could reduce the dosage. I could test for everything else and all seemed to stay in a reasonably stable range. For some reason TDS was continually rising. I started reducing the potassium and the TDS readings also came down and then stabilized. I ended up at about half the original potassium dose. I can go with that and TDS now stays in a predictable range again. I'm assuming (and I could be wrong) that I was dosing more that the plants could use and that is why the TDS was steadily rising. Not seeing any signs of deficiency. I suspect if I do and I raise the potassium dose I will be able to adjust again based on any TDS buildup I see.

That's my theory anyway. It could be a bunch of hooey.:frown2:

Sorry to stray so far from the OP. I'd recommend a TDS meter but as the one I have seems to work very well (I've checked it several times against ones known to be accurate) there are others that are just fine at a much lower cost. If I'd only known.


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## chappy6107 (Aug 2, 2016)

roadmaster said:


> Yes,I agree.
> But my thinking is once I determined what the TDS were by mid week, or end of week with all of the afore mentioned contributer's being present,(that I add directly? indirectly)then this might lead me to consider either feeding/stocking less or change more water.
> I cannot see where TDS meter would be needed on regular basis once you know what you have by week's end and normal tank operation's,stocking,feeding's,fertilizer's,etc.
> If one see's that the target TDS they wish for are achieved with say once weekly water change of 35 to 50 % ,then the meter would not seem as useful unless sudden changes are made to the system No?
> ...


I used to think this way as well. But, as a shrimp keeper & breeder, shrimp are not very tolerant to high TDS. I use my TDS meter to monitor each tank as I use RO water that is remineralized. Once you remineralized say 5 gallons of water with the needed amount of remineralizer, you get a specific TDS. This is very important to keep stable for shrimps at least.

Now in my fish tanks, I once was using a certain dechlorinator. The powder needed was such a small amount that I could not accurately measure for my 55 and under tanks. and since I did not at the time measure TDS, I did not know how much I was overdosing. My fish started dying slowly and I finally checked the TDS after trying many other avenues. The TDS was through the roof. Over the next month I slowly brought down the TDS to normal levels and not surprisingly my fish have been healthy ever since. Needless to say I now monitor TDS OFTEN.


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## natemcnutty (May 26, 2016)

@roadmaster @Nordic Another big use is for shrimp keeping. We don't want to change the water more often than necessary, and TDS can give us a good gauge of where we are at. When adding a hundred new (baby) shrimp a month, it's hard to gauge a lot of things... [emoji14]

Also, plant mass plays a big role in the unknown for me. It's not linear, and I feel like some of my plants take a while after trimming before suddenly going gangbusters. It's just not predictable (or I'm too much of a noob - you pick!).

I like challenges, so I'm running a 20 long high tech shrimp tank that is moderately to heavily planted with a dozen different plants. As I pull floaters, top and replace stems, and other basic maintenance tasks like that, it can be really hard to gauge the impact that will have on fert consumption among other things. Checking TDS actually gives me a decent idea of fert consumption so I can keep my dosing as lean as I can.
@nikohak, I don't believe it is quite linear, but it is honestly close enough for what I'm using it for. You can pick up calibration solution for $10 or less of you are worried about it.

Sent from my Nexus 6 using Tapatalk


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## Wendy1B (Jan 8, 2017)

roadmaster said:


> Forgive me,I am old and have always wondered what do most folks use TDS meter's for in freshwater aquaria?
> Do they come with any information as to what all contributes to Total dissolved solid's in the aquarium?Fertilzer's,fish food's,fish poo,buffer's,substrate bacterial activity, decaying plant matter,basically anything capable of dissolving or going into solution will affect TDS.
> Water change would be quickest way to reduce TDS as well as reducing that which contributes to TDS.
> Do not believe any three tanks would test close to same for TDS unless they were empty of anything other than tap water or R/O water.
> What say ??


 I am going to be starting a heavily planted 12 gallon Fluval Edge after being out of the hobby for a few years. I've fallen in love with Crystal Red Shrimp, and I initially want the meter to determine if my tap water is decent enough to use, or if I'll have to invest in a RO unit. I will be regularly monitoring TDS to determine proper water column fertilizer brands and dosage amounts as my tank needs evolve. I just want to avoid unnecessary Shrimp deaths. I never bothered with this type of hair splitting in my old 55 gallon setup, but I just had fish & plants. Now I feel like going all mad-sciencey in my first ever small tank and foray into inverts. MUAH-AH-HAH-HA-HA-HA!! {*wink*wink*}


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