# Water Softener affects on KH/GH



## sstratto (Sep 2, 2007)

So I have a have a 46g fresh water aquarium filled with water softener water (Ca/Mg->Na). I am calculating CO2 ppm via the pH/KH method. Pre-DIY CO2 I was pH 8, KH 7, GH 5. During CO2 I got pH 7.6, KH 7, GH 5 so the CO2 was about 5ppm. I would have expected it to be more like 10ppm even for a single 2L DIY yeast CO2 setup. The CO2 is injected into the intake of the canister filter. 

So does the fact that my water is mostly Na have any impact on the accuracy or validity of the KH/GH results?

thanks,
Steve


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## hoppycalif (Apr 7, 2005)

The pH/KH method for measuring CO2 in the tank is almost never accurate, and it usually indicates a lot more CO2 than you really have. Get a drop checker, and use it per the DIY sticky thread on drop checkers. That will give you the most accurate measure of CO2.

You will need more than a single DIY CO2 bottle for a 46 gallon tank. In fact, you really need a pressurized CO2 system unless you stick to low light levels.

Water that has been softened with a NaCl charged water softener is not good to use in an aquarium. If you use KCl instead of NaCl it will be much better - plants need a lot of potassium but not sodium.


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## Bert H (Mar 2, 2004)

First off, welcome to apc. What Hoppy says is true. You don't want a high Na concentration in your tank. Why not just use your water without going through the softener?


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