flow rate & PVC question.

[mark]

If you looking for a bulkhead size in your sump to feed your pump should be okay with the same inlet size of you pump (just don't reduce). It's not really a gravity feed since under suction so the 1" can flow more the the 600gph.

If your talking sizing a drain on your display to match the output flow at head from your pump that's different. These two links might be helpful; RC Headloss (use Velocity T4) and RC drain size.