View Full Version : Running Eheim filter under pressure?

01-27-2013, 01:32 PM
I'd like to allow water to pour into the overflow of my 100 gal tank and drain out the hole in the back into tubes to my Eheim canister filter below my tank and then have the water pumped back into the tank. Do you think that arrangement can be made to work without leaking? One reason I like this idea is that I can place my heater in the overflow box so that it isn't visible and lots of water will pass it.



01-27-2013, 01:49 PM
Not sure how that is different than a regular canister setup.

01-27-2013, 01:53 PM
Well, in a regular canister setup, both water in and out go over the back of the aquarium. In this case, water to the canister would be coming out of the bottom of the aquarium. I'm concerned that this difference might create more pressure and cause something to leak/burst.


01-27-2013, 02:27 PM
It is fine as you are pumping from and to the same water level in a closed system. You might worry about if the canister can get restarted if say the power goes out though.

01-28-2013, 10:36 PM
It can work but it isn't quite the same. In a closed system (normal canister in and out of aquarium) the water level is not critical as the intake will draw water up and out of the aquarium keeping the canister pumping water. If the water level lowers enough that there is not enough water to reach the top of the overflow the canister pump will run dry. This is bad for any pump. Most sumps carry a lot more water than a canister so it takes a lot more evaporation to become an issue. You will need to keep an eye on it.