Running Ehiem Return Pump Out of Water

[dlux4life]

Hi Guys-

I made the mistake of poorly designing my sump when I built it. I have a 90 gal SPS tank and a 30 long underneath with two sections, a large refugium and a return section that holds my return pump and skimmer. The ATO is also there to keep the water column fairly consistant. I am going to completely redo the sump when i first can, but cannot get the sump tank out with out draining the display tank.

I bought a new Ehiem compact pump that can run out of water which will give me more room in my return section and should prevent the micro bubbles that I am getting with it at this time. I could hang it over the edge of the tank wall with a tube drawing the water up from the return section.

Is there any disadvantage to running a pump like this long term?

I can fit it so the pump is submerged, but only where the water overflows from the refugium section. The increased output from the pump creates a lot of flow / bubbles which the return pump puts right back up to the display tank. If I can hang the pump, I can draw the water from an area in the return section where there are no bubbles.

Thanks,

[dlux4life]

This awesful diagrams may help out:

The way it is now:

http://i48.photobucket.com/albums/f215/dlux4life/sump1.jpg


They way I was thinking of doing it:

http://i48.photobucket.com/albums/f215/dlux4life/sump2.jpg

[rbirling]

I've thought about this a little bit. You would want to make sure the pump is below the level that the sump water comes up to when the pump is off. If not, it may not prime when you turn it on, or if power goes off and on. A plus is, it won't add as much heat to your water if that's a concern. In your first diagram, you may also be able to put a baffle over the pump so that bubbles don't have a direct path to the pump input. Make the water go around and down so the bubbles don't get there. Normally there's some kind of over-under-over baffle before the pump to get rid of bubbles. Even so, some can make it through depending on the layout. HTH.

(I'm assuming the pump itself is rated for submersed or external use. I don't know if any are submersible only.) -- Just looked at the Eheim Compact pump, it does NOT look like it's OK to run externally, it says, "for use under water". If you happen to have the Eheim Compact+, it's OK for either use.

[dlux4life]

Hi Rbirling-


Thanks for the input. The pump is rated for internal or external use. That section of my sump is very crowded. I'd love to build a dedicated section for the skimmer and put a baffle in before the return pump to eliminate micro bubbles. That is the design for the new sump.

I wasn't sure if this would put additional stress on the pump under long term use.

Thanks

[rbirling]

I guess it would be effectively putting some restriction on the input, which people don't recommend when using a valve to reduce flow. As long as it's not to far from the bottom I'd try it. But YMMV. :-)