Originally Posted by mr9iron

I purchased a Modular Marine 1200 gph overflow that has 3/4 uniseals on the external box to go to the sump.

I ran 3/4 pipe from the box about 8 inches down then coupled it to 1 inch plumbing and immediately installed the gate valve. The gate valve sits about 2 feet above the sump.

The weir is connected via 1 inch bulkheads that go to the external box and flow through the above mentioned pipe.

I cannot get enough flow through the weir to balance the