What will happen?

[misguided]

If i use a 3/4" bulkhead that does 350GPH and use a mag drive with 3/4" inlet and outlet that does 1300gph what will happen?

[Dr. Chek]

be more specific...
3/4" bulkhead is the overflow to the sump???
and the mag drive is the return? how high are you pumping it???
"Throw me a bone, I'm the boss, I need the info!"

[Blown 346]

If the drain size is 3/4 and you use a 1300 GPH return pump you are going to have a tank that overflows since the drain cant handle 1300 GPH.
If that is the case you are going to have to get a bigger drain or drains. Two 1" drains will handle 1300GPH just fine. Otherwise you are going to have alot of water on the floor.

[misguided]

No there isnt a sump im using the pump for flow. So the 3/4" bulkhead will connect directly to the pump and directly to the return

[misguided]

^^^^

[jjmg]

Your using it as a closed loop? From the drain to the pump and back to the tank? What size is the pump inlet?

[misguided]

3/4"

[jjmg]

You may not get max flow if you plumb a 3/4 in drain to a 3/4 in return but it seems as if they made the inlet the same as the outlet for a reason, If it is a closed loop I think you'll be fine. I wouldn't exactly bet on 1300 gph though.

[misguided]

thanks What kind of flow would you suggest for a Fowlr 28 gallon hexagon?