Re: Co2-KH-PH-AARRGGHH!!!

[krombhol at teclink_net (Paul Krombholz)]

    * From: Michael Batts <Michael at whatisdat_com>

Hmmmm, thought I had this stuff licked.  Guess not...  I thought that Co2
lowered PH AND KH.  My tap PH is 7.6 and Kh is 15.  I started with 100 drops
per minute of Co2.  This dropped the PH to around 7 and the KH to around 9.
Good, but not good enough. Time to drop some more.  Soooooo, I increased the
Co2 to 120 DPM.  Viola! the PH started to drop and settled at 6.8, SPOT ON!!
(so I thought)...  Now the KH has raised to 11!!  Run this through a ANY Co2
calculator and it is still bad!!!  I thought the KH dropped WITH PH???  Why
did this happen?  Should I try to drop the KH manually?  I should like to
see it at about 5.  What method is best?  Thanx in advance!!!

---------------------------------------------------------------
Probably all that CO2 and lower pH caused more calcium carbonate and
magnesium carbonate to dissolve, increasing the buffering capacity of the
water.  KH is a measure of the amount of acid necessary to lower the pH
down to four point something---can't remember exactly what.  The best way
to lower KH is to replace part of your water with water that has a very low
KH, such as rain water, deionized water, or reverse osmosis water.

On the other hand, why worry about KH that much?  If your CO2 levels are
where you want them, why worry?  What are your plants lacking?

Paul Krombholz in humid central Mississippi