I drilled my 10 gallon, but don't have anything installed on it plumbing wise except for the bulkhead. I'd say just come out the back of the bulkhead with pvc pipe to a T connector. The T would be going vertical and put a little segment of pvc on the upper end of the T, then put a cap on it, drill a SMALL hole in the top of the cap, and you'd be good to go. Just my 2 cents
HTH
Stewie