View Full Version : Is there any advantage to running your return pump internally vs externally?

05/26/2006, 07:21 PM
Just as asked. If I plan to use a QO3000 as my return pump, is there any advantage to running it in the sump vs outside of the sump? I need all the room in the sump I can get, so if I can plumb this outside of the tank is that ok? Would I be losing any turnover? If so, how much?

I plan to run ~300-400gph through a 5.5g aga sump (i'll cut back as needed.) I can drill the end of the 5.5g tank to fit a bulkhead of the same size as the intake (1"). If this is ok, does it make a difference if I mount the pump above the tank versus next to the tank? This would save me a little space as I have more vertical than horizontal room in the stand.

Thanks for any help:)

05/26/2006, 07:39 PM
personally i wouldnt use a 5.5 as a sump, it would be too small. also i wouldnt trust it drilled with an external pump being the glass is so thin. the difference between running internally and externally is heat. when ran under water, the heat is removed by the water, which can raise the tanks temperature. by running externally, the pump is cooled by air.

05/26/2006, 08:52 PM
I've seen people have 6g sumps, why will 5g not work? I've tried to find plans for these, I know some have done small sumps.

Good point with the thin glass, I guess i'll count on having it in the tank then.


05/26/2006, 08:55 PM
The problem is simply the thin glass. I had a similar setup a few years ago, and the vibration cracked the glass in less than a weeks time.

If you're dead set on using such a small tank, it would be better to use acrylic or making one out of thicker glass.

Make sure that the pump is absolutely level with the bulkhead, ANY stress at all on that thin glass is just asking for trouble.

05/26/2006, 09:01 PM
if you run the pump externally you need to have a bulk head for the sump. or else everytime you shut off the pump or power outages occur youll have to prime the pump or it wont start flow again. as far as heat from submerged pumps. its shoouldnt be that much of an increase

05/26/2006, 09:03 PM
As said above heat would be your advantage. Tank would be cooler with the pump out of the sump.
Two other things to think about when using such a small sump.. 1. Have you taken into account and considered micro bubbles? A small sump like that is going to be hard to displace the bubbles before they hit your return pump. 2. What happens when the power goes out? I assume this sump is for your 36 gallon. Be sure it can hold any extra water pouring down your overflow with no working return pump.

05/26/2006, 09:08 PM
to prevent overflowing when power is shut off set baffles low.

Saltz Creep
05/26/2006, 09:42 PM
For a cooler tank without a chiller I run all my pumps externally, even on my Remora Pro.