my tap pH is pretty low, around 6.2...cardinals will love it though I just bought 10 today for my 60g, will give week or 2 to acclimate and if all well will get 6-10 more in that week or so time. But anyways yea, measure that with my kH I got my CO2 to around 30 ppm according to that chart, which I believe is correct right? Turns out to be a little under 1 bubble...once I finish this inline reactor and switch to that for diffusing, yes I will have to redial my needle valve all over again, but should be nice and easy. Hard work is almost done, and the plants are finally starting to grow, good to be back!!