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Changing KH with KOH or Ca(OH)2
Eric wrote:
> OK. My Lamotte CO2 and KH test kits finally showed up yesterday, so I
> went a-testing. CO2 is at 55 ppm, KH is at 10 ppm, which gives pH of
> about 5.4 (not completely inconsistent with my measurements).
> So I figure the KH needs to go up and the CO2 should probably come
> down. And I think it's likely that Ca levels are low if KH is that
> low, right?
Nope, you've got GH and KH mixed. GH reflects Ca and Mg in the water
column. KH reflects Alkalinity.
When I do a water change I adjust GH with CaCO3 (my tap water has 3.0dGH
but the plants remove minerals, so I have to raise GH, then KH if necessary
with bacarb. Thi has the added side effect of raising pH. Lastly, CO2
injection produces carbonic acid which lowers pH. It's all a balancing
act.
---------------------------------------------
michael rubin
michael at rubinworld_com
http://www.rubinworld.com