I have heard of and experienced several failures, of the cheap check valves. If you can not get the pump above the tank, put it on a shelf above the tank or hang it from the back with a paperclip.
If possible I would recommend putting a nail or screw in the wall above the tank and hanging the pump from the wall with a string. To reduce noise you can put a piece of sponge or styrofoam between the pump and the wall. Putting the pump on the canopy is just asking for trouble...splash!