There is no one 'standard' Cerges design so its tough to say what your problem could be. At best these seem to work well as a glorified bubble trap.
If you just have air accumulating in the top of the canister - drill a small hole in the top - insert an airline tubing and connect to a venturi on the incoming water line. This will pull the extra CO2 out and reinject it in the water allowing it to dissolve. Excess air bubble from the venturi will get trapped in the Cerges. You should see very fast consumption of CO2 and if the water flow is not too high then a bubble free tank.
Unfortunately the basic design on the Cerges described in TPT forums is lousy at dissolving CO2 since the design does not describe a way to increase surface area.
If you just have air accumulating in the top of the canister - drill a small hole in the top - insert an airline tubing and connect to a venturi on the incoming water line. This will pull the extra CO2 out and reinject it in the water allowing it to dissolve. Excess air bubble from the venturi will get trapped in the Cerges. You should see very fast consumption of CO2 and if the water flow is not too high then a bubble free tank.
Unfortunately the basic design on the Cerges described in TPT forums is lousy at dissolving CO2 since the design does not describe a way to increase surface area.