Plumbing Issue

[reefhw]

Hello,

I have a system consisting of two display tanks (58g and 11g), both sharing a common refugium(5.5g) and sump(20g). One of the tanks is an 11 gallon in which I installed a 3/4 bulkhead to use as a drain, and have a u-tube over the side for the return. The return comes directly from a Eheim 1250 placed in the sump (about 300 gal/h with no head, the tank is about 3 feet above the pump). The drain consists of a drilled strainer followed by a 90 through the bulkhead to a T. The upper half of the T is caped and is drilled with a 1/8 hole for air and the bottom half is attached via spa flex to a bulkhead on the side of the refugium. (All aforementioned plumbing is 3/4”) The refugium then has a make sift sand pipe that flows down into the sump to complete the loop.

My problem is that every so often (3 times in the last 6 months) the 11gal tank overflows. Luckily it seems to recover soon after overflowing. This seems to happen right after doing a water change, but not consistently. Any idea what I could be doing wrong with the plumbing?

The only thing that I can think of is the possibility of air getting caught in the pipe between the refugium and the 11gal. The pipe travels down about 2 feet, to the base of the refugium, that back up about 6” to the top of the refugium where the bulkhead is. Although I would have thought the water pressure would have taken care of that.

Any ideas?

Let me know if anything isn’t clear.

Thanks,
Tim

[BruiseAndy]

Sounds like the 58G has a higher water level than the 11G and its backflowing up through the drain piping to overflow. If they do share a common drain seperate them. Picture or piping schematci would be helpful.

[kgross]

I would guess that you are correct, is it possible to change the plumbing so that it does not have to go back up to the fuge? With the loop, the water has to build up a little to restart a siphon after the flow stops.

Kim

[reefhw]

Hello,
No, they both are plumbed separately. The 58g has it's own "normal" plumbing to the sump. I will see what I can come up with as far as images or schematics tomorrow.

Thanks again,
Tim

[BruiseAndy]

<a href=showthread.php?s=&postid=8549465#post8549465 target=_blank>Originally posted</a> by kgross
I would guess that you are correct, is it possible to change the plumbing so that it does not have to go back up to the fuge? With the loop, the water has to build up a little to restart a siphon after the flow stops.

Kim
Don't think he's using siphons for returns. Sure the obvious things were checked for like plugged return piping right?

[kgross]

When the pipe goes down and then back up it makes a loop, the loop will create a siphon when it fills up with water. Until it is full of water it can very easily create an airlock slowing/stopping the flow.

Kim

[toastman]

When the tank overflows, does it overflow at the rim of the tank, or does the water shoot out of the 1/8" hole in the cap on the pipe behind the bulkhead? Sometimes you can get water shooting out of there when the pump kicks back on, and fills the tank, before the head pressure on the drain into your fuge has enough time to begin flowing again. If that is the problem, just extend the pipe out of your T(behind the bulkhead) up 6" or so above where it is now and then put your cap back on it....hope that helps. Another thing to do , would be to add a t in the fuge, where the water enters it from the 11gallon, and run it up above the water level of the fuge, so that it can breathe there, and not build up head pressure....just some thoughts