Originally Posted by mtanec

so long u allow the CO2 to travel through a tube to the filter, the longer the tube, the more CO2 is dissolved..

1 thing to take note.. if CO2 is not well dissolved, especially for canister filter like Eheim, it will cause the filter motor to wear off faster as CO2 is trapped in his filter..

another thing to note for your case, using over head filter is not a recommended setup when CO2 is injected into the tank.. CO2 will escape especially when water is sprayed onto the filter bed before going back into the tank..