return pump size?

oh and keep in mind that the higher you have to pump, the less flow from your MAG you'll get... i'm going to take a wild stab in the dark and say your pumping from the bottom of you sump back up to the top of your tank sitting on a standard stand, aprox 3-4ft high. So that means you'll only see about 270-300gph from that pump. Measure your run but you should be good with either a MAG3 or 4 + a ph or two

 

+1 if you stick to 1/2'' tubing/pipe i think you can follow this chart to a tee.

 

I think i'll go with a Mag 5 based on the Danner Mag-Drive flow chart. i'll have between 3-4 feet of head and i'd rather be alittle oversized than too small. What kind of valve is it that i need to return the excess water back to my sump? i know i'll use 1/2'' flex PVC so i'll need a 1/2'' valve but can't remember what those valves are called...

 

A PVC ball valve. You want a tee in your line just after the pump. Picture a T on it's side... the crossing top will be the line going back to your tank. The other line will need a 90* elbow added that points back down into your sump. Put the ball valve on the bottom elbow to control flow back to your tank.

*edit missed the flex tubing part. you shouldn't need the 90 then. But still put the valve at the end of this line. You'll have better flow control and wont have any back pressure on the pump which will shorten it's useful life + potentially add unneeded heat to the water.

 

it's called a ball valve, but you don't need to Tee it, just put the ballvalve inline between the pump and return outlet and adjust the flow as needed, he Mag pumps are designed to handle the backpressure this will create with no problem.

 

Really? Not mine.

From Drs. Foster and Smith Mag Drive page:

Features

• For submerged or in-line use.
• For freshwater or saltwater.
• Mag Drive pumps are best suited for free-flow setups, where water encounters very little back pressure.
• The pump is magnetically driven - it has no seals to wear and contains no oil.
• Energy used is approximately 1/2 of regular motor driven pumps.

 

you have to remember, your only restricting a small portion of the flow, if your closing off more than 1/4 of the flow with 1/2" lines then you may want a smaller pump, but my Mag 12 has 1" pvc return dialed back about 1/4 with no adverse effects.