Planted Tank Enthusiast
Join Date: Oct 2002
Location: Minneapolis, MN
OK, on some post I remember there was a formula to calculate ppm of CO2. It was 3.6*KH (in ppm?)*10^(7-pH). Well, my KH took 12 drops. Really, I added 2 after the 11th, for a total of 13, but if I assume it changed on the 13th, then I could be over-estimating my KH, hence overestimating my CO2. I converted it to ppm by multiplying it by 17.9.
Well, my pH came out as around either 7.9 or 8.1, so again I will say 8.1 since I do not want to over-estimate my CO2.
So, now for the calculations. I took out my graphing calculator and put in 3.6*214.8*10^(7-8.1), and I got 61.42.... So it says I have 61 ppm of CO2, but then the fish would be dead! I even did it again with a pH of 8.4, just to see if my pH tester if off, and it still came up at 30.7... which is a LOT!
In the formula, is it supposed to be 0.36 instead of 3.6, since then the results would make sence (6.1 ppm or 3.07 ppm seem more realistic). Can someone help me here? Is the formula accurate or am I making a (stupid) mistake?