I did not think that the canister filter would cause a PO problem, I know that they are nitrate factory's but I was able to keep the nitrate within a safe range with water changes. I will unhook it and see what happens.
I agree with Travis, I would remove the canister. The live rock will provide more than enough filtration for you, chances are the canister will eventually become a nitrate source. What are your nitrate readings in the tank?
