I just built a DIY external reactor which is about 20" long 2" PVC pipe with 11 bioballs inside. I am running my Magnum 350 through it and I am still seeing tiny bubbles coming out of the filter exhaust into the tank. Would it work better if I stuck a course filter sponge in there as well as the Bio Balls? Or do you guys have any other advice? I have tried moving it to different degrees to see if that helps but it really doesn't. I do have a considerable drop in PH but I have to keep my CO2 cranked up. I built the reactor to make more efficient use of the CO2 and save my filter. It seemed like I was getting better results going through the Magnum and not using the reactor. By the way the reactor is on the output side of the canister filter.