I know that the tetra check valves usually work good. I have seen them right above the aquarium, and also under water just above the diffuser.
no no. i was placing cv between manifold and bubble counter. i dont know if the problem is casued by that. i dont have pH that thing. 2bubbles/sec for my 20gh, 1bubble/2sec for 5.5g, and 1bubble/2sec for 2.5g. if your tank is open top, co2 24h/day should be fine. pH will keep stable. what kind of plants do you have? what size is your tank? co2 depends on tank size, dissolving completely, and livestock/plants condtion. hope this helps.Luke said:i looked at it again....it is actually the tetra tec....for some reason i thought it was hagen.....i had it at the top of the aquarium with the diffuser inside and at the bottom of the aquarium.....the co2 bottle and bubble counter are below the tank inside the cabinet.....i was gonna try placing the check valve near the bubble counter and try that...but if you had the same problem.....i may not risk it.....do you have a ph swing with it running all night.....and approx. how many bubble per second [bps] are you running......i just started the tank, so i was only running about 1 bps...later i was going to up it to 2 or 3......