Planted Tank Guru
Join Date: Jun 2004
Location: Baton Rouge, LA
Right before CO2 turns on, do a pH test. After CO2 turns on and the drop checker stabilizes at the final color, do another. Remember the colors/readings.
Then you can do a pH test any time you want to get a relative (and unlike the drop checker, instantaneous) idea of how fast the CO2 rises and falls in your tank, and whether you need to turn on the CO2 earlier.