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View Full Version : Recommend a return pump


jhawksoon
06/16/2011, 06:43 AM
I currently have a model 7 mag drive return pump (700gph?) Is this sufficient? The reason I'm asking is because I can only feel a significant amount of pressure coming out of only one of the two return heads. What would you suggest to replace it? I have a 65gal main tank and about 15 gallons in the sump.

greech
06/16/2011, 11:23 AM
The size of the tank doesn't matter quite as much as how high the pump needs to push water from the sump to the DT. There is a head loss calculator on the homepage that can help you determine a good size pump. My preference is to go a bit larger than you think you need (ideally about 3 to 5 x turnover of your total volume per hour) and use a ball or gate valve on the output of the pump if it ends up being too strong.

Unless there is something wrong with the pump or there is a considerable distance the pump has to push I would think a mag 7 should be enough for your tank. Maybe run the mqag 7 through the calculator and see what you should be getting. Also, twists and turns in your piping make a difference in head loss too (which the calculator will take into account).

jinks
06/16/2011, 12:15 PM
You could put a gate valve on the return that is putting out the most pressure and dial it back to even the two out. Sounds like the one flowing harder is just the path of least resistance.

Catastrophi
06/16/2011, 01:14 PM
Putting a gate valve on the pump without a relief will put strain onto the return pump.

pmark
06/16/2011, 06:20 PM
You could put a gate valve and tee off the return to go back into the refugium.

tchndie
06/16/2011, 06:33 PM
Putting a gate valve on the pump without a relief will put strain onto the return pump.

Actually reflow say's if you put a gate valve on the discharge side it will not hurt the pump! It will actually prolong the life of the pump according to reflow!

jhawksoon
06/16/2011, 06:44 PM
I can't seem to find the calculator. Thanks for the help everyone.

jhawksoon
06/16/2011, 06:46 PM
nevermind, found it

jinks
06/16/2011, 08:07 PM
It shouldn't put back pressure on the pump as long as the second return isn't running at full. You aren't restricting the flow you are diverting it. I guess im assuming that the return line goes in a Y to the returns.

snorvich
06/16/2011, 08:31 PM
Actually reflow say's if you put a gate valve on the discharge side it will not hurt the pump! It will actually prolong the life of the pump according to reflow!

That is correct. I do that on mine (two of them)