Can Ehiems be run above water level

[Ti]

I'm looking to get an Eheim, but I 'll need to use it above water level.
Will it get enough suction above water level to work?
If so how far from the water surface can I run it?

[manderx]

it will not prime itself.

[Yinger]

if the water level falls below the suction end it will spit microbubbles back into your tank.

[Ti]

I've used Iwakis above water, so I'm curious if the Eheim can.

[sjm817]

I don't know of any submersible pump that can run that way.

[gcarroll]

Once the pump is primed, it should be no problem. The hard part is priming the pump. I have considered doing this myself to add additional flow through a wave making device but I have never actually done it.

[Ti]

I'm thinking the same thing too, I had to prime the iwaki I used above water, but once the water was in the tube I was able to turn it off an on without any issues.

[clsanchez77]

Everyone covered the major issue which is priming the pump. As far as I know, none of the hobby pumps are self priming (maybe some of the larger/expensive ones are). If it is setup as closed loop, you will only have to prime once and you should not loose prime afterwards (install valves so the pump can be removed and water is not lost from the pipes). If it is not closed loop, you will have to re-prime everytime the pump looses power.

The next issue whcih Yinger mentioned is cavitation. If the pump ecounters more head loss on the intake side than what is on the discharge side, negative pressue will occur in the impeller chamber and dissolved gasses in the water will be pulled out, casuing cavitation. Cavitation will produce tiny microbubbles in the tank and may damage the pump. This can be resolved by ensureing that there is more head loss on the discharge side (smaller pipe, additional fittings, reduced exit...) but will result it drastically reduced performance/efficiency such that you might as well use a powerhead.

In the end, I do not recommend it. These pumps are small and connected via flexible tubing. You should be able to find a small space somewhere that you can get them below the water level, even if you have to cut a small hole in the wall and stick it between the studs...;)

What exactly are you trying to do, we can help come up with alternatives. If your flowrates are not too great, you can use lifter pumps or dosing pumps.

Chris

[Ti]

I'm looking to use it as a skimmer pump.
It's a bit too big for the space I have currently for a Mag, so I thought of running it above water.

[clsanchez77]

Is this in sump or a HOB skimmer? Which skimmer model and/or flowrate thru the skimmer?

[clsanchez77]

Can you go behind or next to the tank/sump and use a U-tube to connect the pump. You will still have to prime the pump, but once it is primed, you will be okay and becuase the pump is below the waterline, you will not have the cavitation issue.

Chris