The first thing that needs to be done after setting up a pressurized CO2 system is to leak check it. The amount of CO2 we use in an aquarium is barely more than a slight leak, so any leakage at all will deplete the CO2 supply rapidly, and it can make you think you are putting a lot of CO2 into the water, when it is really going into the atmosphere. (Greenhouse gas?) Use a soap solution such as kids bubble blowing solution to find leaks. Apply it generously, so it drips, then wait a few minutes and look for tiny masses of bubbles, indicating leaks. When I had problems with fast "evaporation" of bubble counter water I found it was actually a tiny leak at the base of the bubble counter, which leaked the water out.