# Converting gH ppm to dgH



## scolley

Someone PLEASE correct me if I'm wrong, but I think you just divide the PPM by 17.8, so for example, 36 ppm is just a shade less than 2 degrees.


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## Anti-Pjerrot

Its all here:

Water Hardness


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## Raul-7

scolley said:


> Someone PLEASE correct me if I'm wrong, but I think you just divide the PPM by 17.8, so for example, 36 ppm is just a shade less than 2 degrees.


Yep, that's how it's done. But divide by 17.86 for extra accuracy.


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## calfish64

Divide ppm numbers by 17.86 to get dKH or dGH

I get it from http://www.thekrib.com/Plants/CO2/hardness-larryfrank.html


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## Hoppy

There is no reason to want to know either the GH or KH with great accuracy. There is no precise value of either that is the target. So, I find it best to just remember 20 ppm equals on degree of hardness. I can always easily do that in my head, and get all the accuracy I need. If you really wanted more accuracy you could still use the 20 ppm per degree number, then add 10% to the value of kH or GH in degrees to get closer to the true number, again easy to do in your head.


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## selvan777

Rather than trying to obtain a specific PH I find it's easiest to acclimate my fish to my natural PH since it is within their range with no additives aside from API Tap Water Conditioner and fertilizers.

That said, please correct me if I'm wrong, I thought to help maintain a steady PH I had to keep an eye on the buffering capacity by measuring water hardness, whether GH or KH or both even.


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## jaidexl

selvan777 said:


> Please correct me if I'm wrong cause I'm new to this but I thought to help maintain a steady PH was to keep an eye on the buffering capacity by measuring hardness.


That's correct to an extent, but many here including myself have been running zero KH or close to it, and even with CO2 injection it does not allow major pH swings as previously warned by the rest of the community. In a FW PT it's not normally something that should need checking that often. Best thing to do is confirm your source water matches the tank before going in, sometimes outside supplies like the tap can change on you, thus changing tank params over time, or certain rocks or gravel can add or take away from KH. As mentioned, many people here with their planted tanks are running next to no KH for the benefit of plants, so there is practically no need test it as long as the tank's situation is understood and the source water checks out. SW reef tanks and cichlid tanks are a different story, of course, maintaining a high KH will require more effort than maintaining zero.

Edit: you changed your post to include GH, my above response concerns KH. GH has little or nothing to do with pH. However it's important to maintain a steady GH to avoid osmotic shock in fish. Best way I personally do that is add an even amount of GH booster to my RO water at each water change, after topping off with straight RO. My GH has not changed much in 5 years.


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## selvan777

I'm sorry, I edited my post before seeing your response.

I haven't yet bought testers for these but just started looking into it and saw this thread... good timing!

I contacted my water supplier for their test results and it's beginning to look like they only do it once a year... google found one dated may 2008 and when I got a reply from them they only sent me a report dated may 2009.

Could it be that relying on their test results be sufficient provided it's done more than once a year? I think by law it should be done a lot more often.


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## jaidexl

I guess every plant works differently, but I find my test results are off from the treatment plant's as far as nitrogens go, so I never trust them. Have never checked their hardness results because I prepare my own water from an RO unit. No need to worry about what others do that way, only have to keep myself in check. :icon_cool

Incidentally, I have tested my own tap's KH very low, in comparison to all the LFS's on different treatment plants who have very hard water. So I drip acclimate any FW animals that I doubt will adjust abruptly to my tank's low params. Anyway, my point is hardness can very greatly from plant to plant, even in local towns/ suburbs. If you're in a suburban area like mine which has north - south - east and west side treatment plants, make sure you're reading the right report for your area.


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## jaidexl

Good read here > http://www.cichlid-forum.com/articles/gh_kh_ph.php


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## selvan777

That's a very good read... now let me go rest my little head for a few...


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## jaidexl

LOL, I know right. If that isn't too much information it's enough.


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## selvan777

Wow, I really needed that rest... LOL

Anyway, I still don't quite get it.

I'm guessing it implies I need to pay attention to 5 things. Firstly, doesn't that mean I do need to measure KH coming from the tap prior to every pwc to ensure it's a close match (I don't have an RO unit)? Secondly, how do I measure Conductivity?

Cardinals are my main focus and, with this post, hope to learn how to best maintain a pH of 7.0 without spending a whole lot of money if I decide to mess with it that is.

My aquarium is just shy of three months young. I use raw tap water and add only API's Tap Water Conditioner before filling and add Seachem's Flourish Comprehensive Supplement for the Planted Aquarium twice a week. I feed lightly in the morning every other day rotating from flake to frozen baby brine to flake to frozen blood worms and back to flake while throwing in a very occasional treat of some other type. I clean the gravel with pwc of 10 gallons (50%+) every two weeks. I'm only using API's Freshwater Master Test Kit (for now). My flora & fauna is as in my signature except that I've so far only built my Cadinals up to 9. They are all happy and growing nicely.

The pH in both my tap water and in the tank is somewhere between 7.2 and 7.8.

Here is another read I thought quite informative too:
http://www.aquahobby.com/articles/e_adjusting_pH.php


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## selvan777

I forgot to add that I clean the gravel with pwc of 10 gallons (50%+) every 2 weeks.


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## Hoppy

Have you ever wondered how a LFS can keep all of those fish, each "requiring" different pH and KH water without massive losses? I once asked my then favorite LFS about that, and the answer was that they just fill the tanks with tap water and don't worry about it. Shortly after that I quit obsessing over pH, KH and GH. Now I never even test the water. I think it has been demonstrated repeatedly that almost all fish we can buy can easily be acclimated to whatever our local tap water parameters are. Of course there are some places with really bad water, but most of us are more fortunate than that.


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## jaidexl

Checking the tap's params is the only sure fire way to know what's going on all the time, but you don't necessarily have to test constantly. Treatment plants seem to change things up once or twice a year at most, in my experience anyway. If weekly water changes are a small percentage of overall tank volume, then changes will happen slowly enough for you to catch it if you do one round of tap tests every month or two. Even then, if you continue with water changes and refrain from taking action, changes will still be slow and the fish will probably adapt with no problems. It's a rapid change that causes problems, so do the test before doing very large water changes like 50% or more, ignore ph, just check the KH and GH. 

Don't worry about conductivity, like 'total dissolved solids' it's all encompassing and not a good way to keep track of KH/pH. The only safe way to get pH down to 7 is to strip all of the KH away, zero KH RO water (reverse osmosis) or distilled water has a neutral pH (7) since there is nothing left to make it alkaline or acidic. You could keep the pH down by adding acids, but that's not something I would suggest, and most people will probably tell you "stay away from pH down" and whatnot. However there are one or two members in here that will be quick to jump in and tell you how great it is if they see this post. Either way, the cost of acid or pH adjusters surpasses the cost of an RO unit over time.

If you ever get into adding CO2, your pH will probably be around 7, maybe less, even if you do nothing else but add CO2.

All that said, if you're trying to get to 7 for the happiness of a fish, you're wasting your time. The fish will adapt just fine to any steady pH. A steady pH coincides with steady KH which in turn means steady GH, and steady general hardness means your fish's cell walls are not exploding during osmotic shock. You might be seeing now why I test nothing but GH these days, I could call my mom and have her email dad to tell me what color the sky is, or I can just look out the window. Chances are the fish you get will be bought/ shipped in water that doesn't match their natural environment, it's whatever the breeder/ distributor/ seller has in shop, which also means params can continually change as the fish changes hands. Most of these fish we keep are in the hobby still because of their great ability to adapt to the stress of change.


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## jaidexl

selvan777 said:


> Here is another read I thought quite informative too:
> http://www.aquahobby.com/articles/e_adjusting_pH.php


That article seems well thought out, but there's one major flaw.. 

_"A reading under 4 dH means there isn't enough of a buffering system and the pH is likely to drop."_

You won't find many people in this forum that agree with that statement since so many here have proven it wrong already. That article is a perfect representation of the pH myth that has been debunked here. I read half way into the third paragraph and closed the page out. I think that might be the same site with all the inaccurate fish profiles.


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## selvan777

Thanks for all that, scratch that site than, I have.

All this business of water testing and all did make me wonder. Because, truth be told, the last time I kept an aquarium it wan in the same county I'm in now but in a different city and it was more than 15 years ago. At that time I never had live plants and never ever tested anything. I did pwc of 50% once a month and had no problems. So now getting back into it I guess I've let myself be taken in by most of what I read and got my first test kit, fortunately it was only $23.

I'm going to now truly enjoy this hobby again with just a little change to the old pwc ritual.

Thanks again...


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## jaidexl

Yeah, things can be taken lightly, but 50% once a month could be rather harsh on some fish. I had some corydoras that seemed to croak after big WCs. Better to keep them a week apart if they're that big, so the fish are used to it, or else jump down to 15-25%.


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