Overflow Calculations

[coolhandgoose]

Thinking about setting up a new 50 gal tank and looking at setting up a hang on the tank overflow.
If the overflow is rated at 800gph what size return pump would you get. Of course I would expect a certain amount of head loss, I guess the main question is should the return gph be greater or less than the overflow gph?

 

[daugherty]

i use a rio hyperflow 17 for my 75 and it works great

 

[coolhandgoose]

Hmmm.. so just thinking out loud here. The overflow is rated at a certain amount, of course it doesn't mean that it will actually put out that amount at any given time. The amount it does put out depends on the size of the return pump, (ie how many gph it is pumping back into the tank). So by this logic in order for the sump not to dry up the return pump should be rated for a little less than the overflow. Is that right?

 

[daugherty]

yes that is hoe it works. my pump puts out 1000gph at 0head but it is perfect when it get to the tank for the amount of flow that gets to the tank. as long as you done go over the 800gph you will be fine. and what i mean by that is if you get a 1200gph pump and it gets 1000gph to the tank there is still 200gph that has no were to go but flood the tank and make a mess. does that help

 

[coolhandgoose]

That answers it, thanks!

 

[Bifferwine]

You want to get a pump that's rated slightly higher than your overflow. Then you install a ball valve on your return line to control the pump. If your pump is rated less than the overflow, your sump will flood.