What is KH?
Elizabeth Worobel
> 1) What is the meant by the term KH (carbonate hardness)?
Well, we just went round and about with this one last week (Ill answer
the post though since I think everyone else is probably a little gun shy
at this time ... flammenwerfer alert!). KH is
a measure of the temporary hardness or that part of the alkalinity caused
by the divalent cations in solution. Unfortunately, in actual fact
most aquarists are talking about alkalinity when discussing KH. For all
intents and purposes KH is therefore the total amount of
bicarbonate and carbonate in solution.
> 2) What is the effect of KH on plants & fishes?
Depends on the organism. In the natural environment, some plants and fish
prefer dilute waters and some prefer water higher in nutrients and pH.
IMHO most organisms can adapt to a wide range of alkalinity ... its more
important to provide a stable environment than any particular set of
conditions.
> 3) Is there a way to measure KH?
With a KH test kit. These kits dont actually measure KH but do measure
alkalinity (which is more useful anyways).
> 4) What is the best KH for plants? & how do I increase or decrease KH?
Many advocate a KH of 4-5. This seems to work well for buffering the pH if
you want to use C02 injection. Personally, I never worry about it and
wouldnt even consider fiddling around with it ... Im just too lazy.
However, if youre determined, you can safely increase your alkalinity (and
pH) with baking soda (NaHC03) ... add slowly a little at a time.
> From .... a guy that is nuts 'bout FW plants ....
Well, Ive been nuts about aquatic plants for over 25 years and since I
got online Ive had more fun than in many a long year.
Dr. dave.