I use an Eheim 2075 on one of my tanks, can be a pita to get the air all out. Try tilting it from one side to the other-holding on each side for a few moments. U may have the canister too high, or too low in regards to the water level-mine wont work at all if this is not where it should be. The noise stope when U put your hand on the top of it? Try reseating the impeller. I have to put my ear on the actual canister to make sure its running-they are very quiet