You need enough air to get the skimmer working properly.
The water in the bottom of the C02 reactor is a losing battle. You going to be adding every day. If you skip a day or two, you're media will be exhausted. Instead, run a line from the inlet of the C02 reactor to your skimmer cup. Alternatively, you can run the air through another reactor with water in it. That is what I do, I use the BRS mini reactor for that. I have to add water about once a week. If you do this, make sure you use tap water. The water itself won't get to your tank. If you use RODI water, it will be a bacterial soup in a couple days.
Good luck.