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Re: Aquatic Plants Digest V4 #1240

Tomoko and friend wrote:

> There is no reason the pH should be
> going up, especially since it
> didn't when I was using straight RO water.
> Here is what the water is like
> straight from the tap:
> pH:8.5
> KH:9 drops (about 160 ppm)
> GH:4 drops (about 80 ppm)
> After treating with Ultimate (a
> dechlorinator) and Seachem acid buffer:
> pH:6.4
> KH:4 drops (about 70 ppm)
> GH:4 drops (about 80 ppm)
> Then the next day the tank is at:
> pH:7.8
> KH:4 drops (about 70 ppm)
> GH:4 drops (about 80 ppm)
> What is going on!?!?!? Any suggestions?

The instructions on Seachem's Acid Buffer are pretty clear that the
treatment needs to be repeated daily over a period of days, and that
"harder" water requires more buffer.  The alkalinity (KH) of your RO
water is low enough that a single treatment is enough.  The higher
alkalinity of your tap water requires more than one treatment to produce
the same effect.

I think that what happens is that the Acid Buffer reacts with the
natural bicarbonate buffer in the tap water, breaking the bicarbonate
down to produce CO2.  The pH of the water rises when the CO2 escapes
from the water, but it doesn't rise all the way back to the point where
it started because some of the alkalinity has been consumed.

Just keep adding the Acid Buffer daily until you get the result that you
want.  Alternatively you can use CO2 to control the pH.  

Roger Miller