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Re: Increasing GH but not KH?

Gordon writes:

> Is there anyway to increase GH without increasing KH at the same time? I 
> wish to keep my KH at its current 5 degrees but I want to increase my GH to 
> about 10dGH, how can I do this without altering my current KH level?
>  If I add Sodium Bi-carbonate it will only increase my KH level but if I 
> Calcium Carbonate it will raise both GH & KH, is there any chemical I could 
> add instead that will only affect GH? Alternatively, is there a way to 
> decrease KH without altering GH?
You can decrease KH by adding any pH reducing chemical. My favorite is 
muriatic acid which I water down to about 7% HCl.  You might prefer nitric or 
sulfuric acid, as calcium chloride will sometimes precipitate, leaving a 
lower GH.  Calcium hydroxide or magnesium hydroxide will also work, but can 
react very quickly with the water.  Add slowly.  These will increase pH, and 
then you will need an acid to bring it back.

>  The reasoning behind this? Well I originally had my GH & KH levels at 
> 8deg each but I was finding I needed to inject a lot of CO2 to reduce my pH 
> down to around 6.9 - 7.0, roughly about 4 bubbles a second through a Dupla 
> Reaktor 400, and the CO2 concentration was also a little too high for my 
> liking (about 30mg/l).

And so because you've had a little shift in GH and KH, you have decide to 
play around with your water?  Are you trying to obtain those original levels 
because you think your fish and/or plants will be better off there, or is it 
just something you want just because you have decided YOU like it better at 
8 ?  There really is nothing wrong with the hardness levels you currently 
have, and doing nothing is both cheaper and safer.

I keep South American fish, and like to get them to breed.  Therefore I 
soften my water.  Not in my rearing tanks or my display tanks.  Just the 
breeding tanks.  The plants do well in all of the tanks, and I know that it 
isn't that critical whether I keep plants in 1 GH or 5 GH.  Maybe you are 
keeping a plant that requires very high GH.  In that case, it is probably 
also adaptable to high KH, as the two are usually both interconnected in the 
wild.  So increase both if you want by doing something simple like putting 
crushed dolomite in the filter.  Remember the KISS rule.  Live by it and your 
fish and plants will be happier and better off.

Bob Dixon