jcbyrne

In his article in the Tropical Fish Hobbyist that just arrived, Amano says that to monitor CO2, measure the ph just before the light goes on in the morning, and again four to five hours later. If it is higher, the amount of CO2 is insufficient, if it is slightly lower, the amount is adequate. If it is much lower the amount of CO2 is excessive.

So, what do you think? What is "slightly lower", "higher" or "much lower"?