measuring pH drop: is this the right way?

[Cor]

I read a lot about the "pH drop" but I have difficulty to find out how to do this.
So please correct me if I'm wrong;

- Take a cup aquarium water and let stand for 24 hours
- measure the pH of this cup after 24 hours
- measure one hour before the light goes out, the pH in the tank
- the pH in the tank must be 1.0 to 1.2 point lower than the pH inside the cup - then you have about 30 ppm CO2

Is this the correct way?

cheers Cor

 

[tim]

Measure the tank as lights come on Cor, this is when the plants require the co2 to be optimum, other than that the method above is correct.

 

[Cor]

Thanks Tim!