One the the 2217's I bought was 2nd hand and one of the quick valves was broken so they have the hoses attached to the intake and outtake via a hose clamp so I couldn't prime it a normal way. The method I found ( which once done, never needs to be done again as long as the spraybar and intake are still in the aquarium ) is simple, after installing everything and opening the valves simple open the clips around the head of the canister and lift up slowly. This will create a suction force which will fill the canister. Either use a light or someone else's help to see just how high the water is rising inside, and before it fills it push the lid back down ( it'll have a little fight to it ) and reclamp the lid. I tried numerous times to just fill the filter with water and turn it on but it never worked. Once you have it primed though all you have to do is close the valves, loosen the connectors and pop the canister out. When you bring it back and theres no water in the canister, hook it back in and open the valves it'll take care of the rest