Maximizing O2 is always good and you are doing it in the right way (surface rippling is better than air stones). Inexpensive ($20-$30) skimmers are also excellent for gas exchange. Keep in mind that O2 and CO2 do not interfere with each other, i.e.; one does not displace the other.
Most of us target a pH drop from fully degassed water to fully gassed water ranging from 1 full pH point to a ~1.4 point drop. This can be done by letting a glass of tank water sit out for a day or two (can be accelerated by aeration), then measure the pH and compare it to your tank about two-hours, or more, after the CO2 is turned on. A one-point drop gives you about 30ppm CO2 and is a good starting target. Make sure that your KH readings remain identical in both the tank water and the sample water.
However, do this slowly, a little every day, until you reach your goal. Turn the CO2 up until your fish show signs of distress (usually gasping for air at the surface or lethargic near the bottom), then back it down a little (until they are happy) and wait a day to increase it further. It can take a number of days, up to a week, until fish adapt.
In your case, it seems that your fully-degassed water is pH 8.0. So, you would slowly move toward a target of 7.0 or less (6.5-6.6 is probably going to be the limit of what your fish can handle).
Most of us target a pH drop from fully degassed water to fully gassed water ranging from 1 full pH point to a ~1.4 point drop. This can be done by letting a glass of tank water sit out for a day or two (can be accelerated by aeration), then measure the pH and compare it to your tank about two-hours, or more, after the CO2 is turned on. A one-point drop gives you about 30ppm CO2 and is a good starting target. Make sure that your KH readings remain identical in both the tank water and the sample water.
However, do this slowly, a little every day, until you reach your goal. Turn the CO2 up until your fish show signs of distress (usually gasping for air at the surface or lethargic near the bottom), then back it down a little (until they are happy) and wait a day to increase it further. It can take a number of days, up to a week, until fish adapt.
In your case, it seems that your fully-degassed water is pH 8.0. So, you would slowly move toward a target of 7.0 or less (6.5-6.6 is probably going to be the limit of what your fish can handle).
