Ya sorry, that was my scratch notes. The only reason I have it that big is because I have 2 of these....
2" bulkheads out/in the 40gal. The out flow does not have power, just a 2" outflow to an over flow box where the pump picks it up, runs through a radiator style chiller w/ 1"PVC and into the 275gal. The other pump w/ valve splitter and 2 leads (one to the 275gal and the other to the 5gal mixed nutrients bucket, for controlled mixing) runs through the chiller and then from 1" up to 2" PVC and through the bulkhead. Make any more sense?