I think Jonathon may have meant the 403, which was the round fluval canister filter that was out before the 404. It takes me about 1 minute worth of pumping to get my 404 started. I fill my canister up with water before I start the priming process. Then, I take the intake hose and fill it up as much as I can. Just dip it in your tank and lift it up to let the water run down it. Then I use the pump untill I see water come out of the filter. (Hose, that is) I then plug it in, and 9 out of 10 times it starts right up. I will say that water level in your tank will hinder you in starting it if the level is very low. I keep my level about 5 to 6 inches from the top in my 55 gallon tank.