drilling holes into tank, bulkhead size?


Premium Member
I have an 58g Oceanic tank sitting around collecting dust the last few years. I'm wanting to put it to use. I plan on drilling four (4) holes, two for draining to the sump, and two for returns that will be attached to a SCWD on a Mag12. What size bulkheads do I need, will two 1" bulkheads be enough to handle the drain flow? Or should I go with two 1.5" bulkheads?


Premium Member
With a mag 12 running into a scwd the 1 inch will handle the flow, but incase you decide to change the flow in the future I would suggest going 1.5 inch.


arc eye

New member
I just finished the closed loop on my Oceanic 58g. I did six 1" bulkheads, 3 intakes 3 outputs. I am using a reeflo snapper as the circ. pump. Its rated up to 2400 gph. I haven't experienced any cavitation, but if I could do it again I would have done bigger bulkheads for the intakes. After adding strainers and everything it really makes the 1" pretty small.

By the way, what size sump are you using? that's a lot of flow for a sump of small or moderate size. I'm using a 40g breeder that I converted into a sump based on a design I saw on Melevsreef.com it will be run off its own separate smaller pump.


Premium Member
I like 1 1/2" for drain lines. It is not so much flow but they are less prone to getting clogged than 1" lines.


Drug Enthusiast
FWIW: I bought a 40br from a LFS that was going out of business, it had a 1/2 inch hole drilled in the bottom for a drain. Yes one-half of an inch wide. Anyways, it's worked out great for me, I've been easily draining 250 gph through it.