How to correctly measure CO2 levels?

[saugata]

Hi! All,

I would like to have a fare amount of idea of my CO2 level in my planted tank. For this I am planning to use either Bromothymol Blue or Phenol Red as the indicator solution. My question is which one is a better indicator solution and what is the correct procedure for using either of them?

Thanks in advance for your help.

[vinz]

Ummm... I'm not sure how accurate the chemical tests are. The commercial hobby-grade kits certainly leave much to be desired.

Some of us use the pH-KH calculations to determine the CO2 levels. We have a calculator for it. The link is at the top right hand corner of the page.