I cleaned my canister filter (Fluval 406) for the first time. I took out the holder with the sponges and media baskets. I rinsed the baskets, canister, and sponges, cleaned the impeller, rinsed out the canister, etc... I put it all back together, reconnected it, and primed the pump. The canister filled up and I turned it on. After I turned it on a bunch of debris came out of the outlet. What did I do wrong? :-?