Flora,

How calibrated do I really need it? This is a simple observation, and to me if I take something that has 50ppm dilute it 50% with RO water to 25ppm that seems pretty calibrated to me. I don't care about absolute values I only care about relative values and for this purpose an uncalibrated test kit will work fine. I just want to know what if anything is causing 1) the KH to increase or 2) if the KH isn't increasing what substance that is being produced in the tank causes the KH kit to be innaccurate.



Neil,

I use straight flourite




Tom,

I don't really care how much KH is in the tank, the CO2 is fine, I'm not woried about it being a nutrient. I just want to know what would cause the above increase? Any ideas would be greatly appreciated. Are there documented cases where either bacteria or plants excrete KH?