i am currently running 3000 gph on a 650 and it works fine.
you can reduce the pump output with a valve on the output ( if its a centrifugal pump) and this will reduce the current draw as well if it seems too much flow.
if it is a pond dont use a sump.....use several 55 gal plastic drums filled with bio media.....use some of the return water to spray over the bio media and use a gravity return.....
you can reduce the pump output with a valve on the output ( if its a centrifugal pump) and this will reduce the current draw as well if it seems too much flow.
if it is a pond dont use a sump.....use several 55 gal plastic drums filled with bio media.....use some of the return water to spray over the bio media and use a gravity return.....