# ph / gh / kh



## klc9100 (Apr 14, 2009)

i have a malawi cichlid tank. my tap water is soft and has a low ph. i've been experimenting with the diy buffer recipe from the library (baking soda, epsom salt and non-iodized table salt). my gh is good now (16) but by the time i added enough baking soda to get my ph up to (8.4), it made my kh (27). from what i've read, that's WAY too high. is it bad for the fish? if so, how can i lower the kh without bringing the ph back down too?


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## prov356 (Sep 20, 2006)

I wouldn't focus on striving for a specific pH value. Instead, bring your KH up to about 8, and it'll stabilize
the pH within a perfectly acceptable range. Why are you shooting for a pH of 8.4? I'm guessing 
something you read, but don't believe everything you read.  Most fish will do fine within a range of 
values. My tanganyikans do great at 7.8, and from what I've read, malawi's will as well. Note that the 
range given in the Practical Water Chemistry article for lake malawi is 7.4 - 8.6.


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## klc9100 (Apr 14, 2009)

prov356 said:


> I wouldn't focus on striving for a specific pH value. Instead, bring your KH up to about 8, and it'll stabilize
> the pH within a perfectly acceptable range. Why are you shooting for a pH of 8.4? I'm guessing
> something you read, but don't believe everything you read.  Most fish will do fine within a range of
> values. My tanganyikans do great at 7.8, and from what I've read, malawi's will as well. Note that the
> range given in the Practical Water Chemistry article for lake malawi is 7.4 - 8.6.


thanks. my kh is 27 though. how can i lower it without drastically effecting the ph? should i just let it fall naturally as i do water changes, or do something specifically to get it down? so are you saying that ph & gh don't really matter, just concentrate on kh? all of this is very confusing. lol.


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## prov356 (Sep 20, 2006)

> so are you saying that ph & gh don't really matter, just concentrate on kh? all of this is very confusing


Check out 'Practical Water Chemistry' linked above. It explains the 3 pretty well. But, focus on KH, 
and your pH will stay stable. There's a relationship there. Stability is what you strive for more that a 
specific pH value. There's some debate regarding how much to worry about GH. And, many aren't 
proponents of adding the table salt. I like to keep things simple and use source water as is, if 
possible. But, if your KH is low, then some type of buffering for rift lake cichlids is a good idea. Use 
the buffers like sodium bicarbonate to raise the KH value up enough to keep pH stable, rather than to 
just raise pH. pH will rise as a result, but the goal is to 'buffer' it against swings or sudden drops. And, 
personally, I wouldn't worry about raising GH unless it's really low. What is the GH or your tap?

Hope I haven't confused you more.


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