I want to put a sump on my tank, and it looks like some people just run their co2 into the return pump. It'll chop up the bubbles for you and send it into your tank. That way you wouldn't need a canister or a reactor. However, I don't have any experience with a tank that size. You might need two points of diffusion and/or powerheads to make sure the co2 is distributed throughout your tank properly.