How high up should my inlet be?

[Jason]

Im making a 55 gallon plastic barrel up-flow swirl filter. It will be right behind the spill way of the pond a 4' from the pump.
Im running 1" bulkhead in from a 1,200gph pump for good pressure for the swirl effect. Was wondering How high up should the inlet be from the bottom of the barrel for the solids to settle on the bottom? 6", 8"?

I will be installing a 3" shower drain on the bottom with a 2" ball valve for flushing the settlement. Thanks

 

[DrCase]

I all ways send the in coming water down from the top to the bottom, and then let it work its way back to the top.

 

[Jason]

Wouldn't that just keep the bottom stirred up and for nothing to settle?