What size return pump?

[pallidamors]

I bought a used hob overflow off ebay a few months back. From what I remember I believe the guy told me it flows 700 gph. What size return pump do I need?

[Michael]

it depends on your system, whats the size of your sump, if its for example 40 gallons then a return pump of 200-300 gallons will be fine, but a mag 7 can handle 700 gallons

[pallidamors]

90 gallons...what Im curious about is how do I make sure that the return doesnt drain too fast or too slowly?

[Sugar Magnolia]

It also depends on how far the return will be. GPH diminishes with head height.

Edit: You can put a ball valve on the return line to decrease the flow as needed. Or split the return and have some go back into the sump or refugium.

[Michael]

well you need to make sure the plumbing can handle the 450-600 gallons of water you will have passing through the sump every hour, and i assume as its a hob box then it is gravity fed and so should work just fine if the size of the plumbing is adequate, the water dropping t the sump should be in a pipe twice the size as the water from the return pump back to the tank

[pallidamors]

thanks guys...so its something I have to play with and tweak