[Gafi]

So I tested my aquarium water and I got aph of 7.0....I took a sample of aquarium water, left it out for 24 hrs, and retested....ph is now about 8.0....If I remember correctly, does this mean I have roughly 30ppm of CO2 in the tank?

 

[Hoppy]

It means that the amount of CO2 in the tank water is about 10 times as much as the sample had after sitting out overnight. But, that amount could be anything from about 1 ppm to 5 ppm. So, you can only assume that your tank has from 10 to 50 ppm of CO2 in it.

 

[Gafi]

ok perfect! thanks!