Ive found the leak. Its the lid of the diffuser. Even after the co2 is off, I still have bubbles going in through the spray bar. If I wiggle each hose on the diffuser no more bubbles go in through the spray bar. But when I move the top hose (lid side) with the hose barb loads of o2 streams the tank. If I clamp the diffuser tightly, by holding tje lid on more the bubbles stop. But the lid is as tight as I can get it. Took it apart, checked the o-rings,. They all look good. Only thing I can try now is grease. Which one is it thats safe?