Originally Posted by
geo57
I had a similar problem with my eheim pro 2028 or something like that. I bought the largest Eheim pump with the heater in the pump and put it in my brand new 450 gal acrylic tank. Was cycling tank with a bunch of tetras, came home one day from work and tank just didn't look normal, pump was running, but tank looked stale and cold. Touching the water it was cold, with the heater in canister and no flow water was not heating up. Now this pump has two inlets and one outlet and I could not get it to start pumping for jack, I took it apart and tested the pump and it was working, but it would not move water. Filled the canister fresh and fixed a jig to test with and I could not get it to flow. After a few hours I gave up on my test jig and installed back into my tank, still no go. Pushed that damn priming button a thousand times and then suddenly it started to flow, first just one inlet, then I would squeeze that closed and the second finally started to flow also and bara bing bara boom it kicked in and hasn't flinched again. I installed a second pump, a Fluval 405 and placed it inline along with the eheim and the large Marineland HOB. I also bought a Fluval FX6 in case either of the pumps On there now fail. I never turn off the canister pumps, I leave them on even when I clean the tank so when the water level drops I can see how much flow I'm getting from my pumps.