External Skimmer output question

[D_Reep1106]

Hey random question and probably a pretty noob-ish question. I've never ran an external skimmer and never looked into them until now. I have a Reef Octopus SRO-5000ext. My question is, does the drain have to be above the water level of my sump. AKA does it have to gavity drain or does head pressure matter? It would only be 6" or so

 

[Brew12]

Hey random question and probably a pretty noob-ish question. I've never ran an external skimmer and never looked into them until now. I have a Reef Octopus SRO-5000ext. My question is, does the drain have to be above the water level of my sump. AKA does it have to gavity drain or does head pressure matter? It would only be 6" or so

I believe all external skimmers must gravity drain. I have yet to see one with a "return pump" that could overcome any amount of head pressure.

Edit: Of course, now that I say that, I think it may be able to work based on elevation change.....