Plumbing confusion

[cjrudy]

The drain pipe in the overflow is 1 1/2 inch but the bulkhead is only 1 inch which means the remaining plumbing from the drain bulkhead into the sump only needs to be 1 inch? I have already plumbed the rest out with 1 1/2 inch which is pointless because the flow is limited by the bulkhead, right?

 

[ljr]

not pointless, but your flow is limited to the bulkhead, the extra diameter will allow for more O2 exchange, but also more noise.