Eheim Professional 4+ not starting normally

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Jeremy G

Registered Member
Original poster
Jan 15, 2017
Hi all,

I rinsed / changed out media in my Eheim Professional 4+ canister this morning, and it's not starting normally. It normally spits and spurts a little as it starts up and then gets to a quiet, steady flow of water, but today it isn't getting there. Appreciate any thoughts on what may be going wrong!


Global Moderator
Staff member
Jan 11, 2013
West Falls NY
Real Name
I tilt and tip them around until most of the air is purged out and they start pumping normally. I do not own any Eheims though. Only Marineland and Sunsun canisters which also have primer buttons that work to an extent.

I always pre-fill my canisters as well.
Apr 2, 2002
New York
Pre-fill is the answer. Over time priming pumps in canisters will only cause issues. The last time I used the priming button in one of my Eheim Pro II, it caused a leak. I needed to disassemble the head with the motor etc, and replace the gasket that is there to prevent leaks through the priming pump. The filter is now fine. Fortunately I had a spare canister on the shelf and was able to swap out the head until I got the needed gasket and replaced it.

Depending on the filter model, how much air can be in it before it wont restart correctly varies. There is a way to minimize this. I cannot say how it is with other brands and models, but the Pro II closes off the intake and return hoses when they are disconnected to clean the filter. The hoses remain filled with water. I wait until I have mostly refilled the tank with new water and then I reconnect the filter and open the taps. gravity does the rest and water flows downjhill though the intake hose and any air in the filter expells via the return hose. The Eheim has taps built in. If your filter doesnt have them, install two ball valevs close to where the water enters and leaves the filter. Close them both before removing the filter to clean it. When you return the filter and reconnect the hoses, open both of the ball valves and let the filter self fill. The more you fill it before you put it back in place, the better,