big plumbing leak!

[psyrob]

I recently drilled a 10 gallon tank with two 3/4 inch overflow bulkheads that drains into the sump of my 60 gallon tank. I use the 10 gallon for a frag tank. I used T barb fittings on the bulkheads, and attached flexible tubing (non-kink type) to the two barbs. On the top of the T I put a cap with a small hole drilled in it to vent air sucked into the bulkheads (they are up at the water line). The two lines come together into another T behind the tank and then drain via more flexible hose into the sump.

Everything worked for the past 6 weeks, but now the water is surging up and down in the T's that are attached to the bulkheads and the water is intermittently splashing out the holes I drilled in the caps. This happened overnite on Sunday and at least three gallons of water had shot out onto the rug...There are no other leaks, when I take off the caps of the T's and look down, I see the water rise and fall as it leaves the bulk heads. When I look at the other end of the drain line, the water flushes full for about 30 seconds, then stops flowing altogether for 5 seconds or so, then rushes out again!

What have I done wrong? My first guess is not using rigid PVC pipe...Thanks for any input

[bhbell]

What size is the hose you're using from the sump up to the T? If you have two 3/4" lines joining together into one 3/4" then you're probably overdriving it. You're onto something by talking about changing over to rigid PVC. The barb fittings reduce the effective size of the hose where rigid schedule 40 fittings generally maintain their rated ID. If it was mine I'd go with 1" sched 40 from the bulkhead T's to a 1.25" or 1.5" single line into the sump.

[psyrob]

Yes, I'm using the same size hose after the T where the two other lines come together. I think I will switch to rigid PVC, but I am stuck with the 3/4 inch bulkheads, I don't want to redrill the tank for a bigger bulkhead. That will eliminate the "pinch" of the barb fittings. I'll have to figure out how to add the wider diameter line after the T that joins the line...

[miwoodar]

PVC is the route to take. I also added a vent to the end of my drain line to make sure no air gets trapped. It's much like the vertical standpipe used on recirc skimmers.

[bhbell]

The 3/4 bulkheads are adequte for what you're trying to use them for. Are they barb connection bulkheads? You can either buy or assemble a T fitting to take your two 3/4 lines from the bulkheads and feed into a 1.25" or larger line to your sump to fix the problem.

[jefnalyssa]

Increase the 3/4 pipes right before the T. Just make sure the T fitting is ithe larger size (1.25 or 1.5) If not you would do all that work for nothing.

[psyrob]

Thanks for the input...The bulkhead is threaded on the outside and I used an elbow that is FPT on one side and barb on the other. I went to OSH this weekend and bought the connections and pipe to make a rigid 3/4 inch connection from the two bulkheads down to a 1 inch T. I slid a coupling in the 1 inch T and the 3/4 inch pipe fits right in there.

Here's my next problem: It looks easiest if I could find a one inch diameter flexible spa hose to run from the 1 inch T down to the sump. If I run rigid 1 inch PVC pipe from the T to the sump, I have three right angles to make: The frag tank sits at a right angle to the main tank (1 right angle). The drain line would have to go behind my tank stand (2nd right angle) then make another turn to get to the sump (3rd right angle). WIll that impede my flow too much?

[bhbell]

Spaflex is great stuff. It has the best features of both flexible hose and full flow connections of rigid pvc. Of course the down side is that it costs more than either. It will actually help the flow by creating sweeping curves instead of sharp bends.

[bhbell]

You may want to got to the 1.25 " spaflex. Mathematically your two 3/4 lines have a combined area of .88" and the 1" gives you an area of .78"