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Re: KH1 etc, related question (LONG)

> Date: Thu, 27 Dec 2001 09:23:48 -0500
> From: David Modine <modine at erols_com>

> I have been following the replies to John Russo's question with much
> interest. I would also like to raise my KH without having my pH
> skyrocket. I keep basically 2 types of tanks.

The only way to raise KH and not have pH "skyrocket" is to slo-o-o-wly add
sodium bicarbonate and slo-o-o-owly adjust the CO2 injection rate to keep pH
relatively constant. pH is going to rise when you add KH. Period. You have
to balance it carefully to have a small pH change. But, see below.

> I change water in these tanks so frequently that the tank's pH seldom
> drops much. It tends to stay around 7.1 to 7.2. The potted swords,
> anubias, & Java's grow "OK".

Slo-o-o-wly adding KH and CO2 with frequent water changes will become a
hobby in itself. Probably not what you are after.

It sounds like you should leave well enough alone. If you want to use CO2 to
help plant growth, you will have to deal with pH swings.  But, as pointed
out by the fellows in San Francisco, fish aren't very sensitive to pH
swings.

For example, we do 50% water changes in our discus tank every other week.
Our water has little KH so we add the right amount of sodium bicarbonate at
each change. When we are through refilling and start the pumps to mix the
sodium bicarbonate, the pH goes to 7.7 or so. The Ph controller will bring
it back down to 7.0 within an hour. We have been doing this for 15 years
with no observable problems. Does a change of 0.7 seem like a lot? It
doesn't seem to bother the fish. Your results may vary.

> Is there a specific buffer anyone would like to recommend me to use in
> these tanks? I have tryed:
> "Discus Buffer", no good, too much algea from the phosphate.
> Muriatic Acid, no good, wipes out the KH
> "Acid Buffer", supposedly good for planted tanks, but a lot of Discus
> folks on various forums are leary of it.
> Kent Marine's "pH Control Minus" , my current choice as it claims to be
> phoshate free, & is the most economical of the brands I have tryed.

Here is an important bit of information that most people seem to miss (but
you seem to know about). Acid and acid buffers will lower pH by lowering KH.
If you add KH for whatever reason then use something besides CO2 to lower
the pH, you are simply destroying the KH you added. The only effect you are
achieving to raise the sodium levels in your water.

George Booth in Ft. Collins, CO (gbooth at frii dot com)
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