Closed loop question

Joe Cool

New member
The input to my pump is 2" does that mean I have to drill a 2" hole in the tank or use a 2" bulkhead which would be around a 3" hole in the tank? thanks


In Memoriam
You want a 2" bulkhead minimum and its usually better to go larger on the suction side for less restriction, maybe 2.5" to 3" so that will require a larger hole be drilled.


Premium Member
Or you could go with 2 bulkheads. Both being 1.5" each. That's how I plumbed my Dart pump on my closed loop and it works pretty good.



In Memoriam
Two 1.5" bulkheads just barely gives you more surface area than a single 2". A 2" equals 3.14 square inches and two 1.5 " combined only equals 3.53 square inches. With the additinal fittings required to plumb the two together you might actually be better off with a single 2". Every elbow, inch of pipe length and valve adds a head restriction while a straight short run of 2" adds very little resistance. A single 2.5" equals 4.9 square inches and a single 3" equals a whopping 7.07 square inches.
Just something to think about.


New member
<a href=showthread.php?s=&postid=9259561#post9259561 target=_blank>Originally posted</a> by Joe Cool
So would two 2" bulkheads suffice?


Also, there will be some redundancy having 2 b/h's feed the pump. If an anemone, or fish ect. happens to get stuck on one of the intakes, you will have a backup.

Anemones WILL still get sucked through though. (learned the hard way)