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Re: [falling] PH and KH

> Date: Mon, 15 Sep 1997 08:40:58 -0700
> From: "Sherlock W. Wong" <wong at dt_wdc.com>
> Does anybody know how to stabilize PH and KH without
> using CO2?

Normally, KH (carbonate hardness) is used to stabilize pH. CO2 is used
to *balance* KH to produce a specific pH.  
> My tap water is:
> 	PH 8.5
> 	KH 5
> The tank water rapidly goes to PH 6.5 and KH of 1.

Normally, the only thing in an aquarium that lowers KH is the
nitrification process.  Two factors are at work: decomposition of
waste products uses small amounts of bicarbonates and the H+ and NO3-
generated by nitrification is equivalent to titrating the water with
nitric acid; the H+ ions combine with bicarbonates to form (I think)
water and CO2. However, this shouldn't happen "rapidly".  In our
tanks, we don't see a KH change in two weeks (between water changes).

How big is your tank?  Is it overstocked?  Are you adding any
chemicals besides baking soda?  Something seems to be producing more
acid than it should.

How do you measure KH?  Perhaps something in your water is
interferring with the test. 

> Will PH buffers help?

Baking soda IS a pH buffer. Commercial buffers usually contain
phosphates which you produce algae.