I have a 180g with three canisters running. I am only home about once a month (I am away at college so im usually home for only one weekend a month) and i just got home to find my Fluval FX-5 is not working. There is little to no water flow from the output, and the canister sounds like it is trying to pump but failing, as if there is alot of air inside or something. It sounds exactly like a hang-on-back sounds when u first start it up (that churning water sounds before it gets the flow going). I tried purging it several times to no avail. It has been over 24 hours since i noticed the problem, so it is definetly not the "2 minute" air evacuation thing it does. I have a plane to catch in 2 hours, and alot of other things i need to get done before i leave, so i really dont have time to disconnect it and empty it out and try to clean the pump housing, but the filter is only a month old and shouldnt be too crapped up already. I will not be home for another month, so i am pretty worried. The two other cannisters (fluval 404 and eheim 2217) can handle the tank, but the fx-5 was my compensation for not being home to do heavy maintaince and now it doesnt work. Any quick troubleshooting ideas?