I ordered the bulkheads as a kit. They do have a filter piece for the inside of the tank. I have 2 more questions.
1. Inside tank at the bulkhead, would it be better to have a 90 elbow facing up, with notches cut into it, acting as surface skimmer/overflow. Or, just leave the bulkhead 1/2 inch or 1" approx. entirely below the water line with no 90. Just the straight filter piece to stop fish from going in.
2. Outside tank at bulkhead, is it necessary to have a "T", with a vent at top of T, or would a 90 elbow going to sump with no vent be better.