unintentional aquarium drain

[rsarvis]

I have a new 180g AGA built-in-twin-overflows set-up that has had sand and saltwater but nothing else for a couple weeks. Yesterday, before work, I shut off the pumps, and when I returned late at night, several inches of water were gone, so I looked down in the sump, and sure enough it was filled to the top. Luckily, it didn't overflow, but it was within a centimeter of doing so--yikes! Anyway, it appears likely that my return plumbing had reversed flow and had siphoned the water off the top, and that was the main problem. So that's a lesson learned; either I should be more careful about the placement of the returns or in shutting off my pumps, or I should install some anti-siphon valves.

 

But there appears to be another problem, because one of the overflow chambers in the tank was copmletely drained as well. So here's my question: Is there any explanation for this other than some sort of leak in the plumbing of the overflow draining thingamajig? It doesn't appear to be too big of a concern, since the water all stays within the system, but I'd rather not have a small concern that might some day evolve into a bigger concern. Thoughts?

[zoozilla]

Was PVC glue used to attach the bulkhead to the drain and return pipe in the corner overflow? If not, that's likely where it's leaking back into your sump and in turn fully emptying out one of the corner overflows.

Edited February 1, 2007 by zoozilla

[jason the filter freak]

I think with adding live rock to your tank the amount of water you'll displace will allow you for play with your sump. It will give you a nice buffer, even if you install an insump skimmer. You're fine it sounds like to me, unless I missed something

[YBeNormal]

Not having pictures makes it kind of hard to say for sure what the problem is but I can make two recommendations based on my experiences. First, your sump should be sized to hold normal operating volume of water plus whatever would drain down from the main tank when the power is turned off. Having a little bit of extra sump capacity on top of this is good for piece of mind. No matter how well you plan, you will eventually lose power or turn off a pump by mistake eventually, so getting this right is a must. It sounds like you got lucky this time but I wouldn't tempt my luck.

 

Second, you should have siphon breaks on your return hoses. Otherwise the water will back siphon into your sump when you lose power. A siphon break is simply a small hole drilled in the hose or fitting inside the tank. Drill one or two small holes just above or around the normal high water mark. When power is lost, the hole will allow allow to enter the hose and break the siphon. You will want to check the hole(s) once in a while to make sure they are clean and unobstructed. I recommend against anti-siphon or backflow valves. They cost money, they will gum up or wear out eventually and it's almost a guarantee that they will fail at the worst possible time. Drilling small holes is easy and they are free!

[dhoch]

Raf... A) what Yb said...

 

B)...do you have stand pipes in your overflows? (solid or tubes with holes?)

 

Dave

[Coral Hind]

I agree with what Zoozilla said. I had the same thing a long time ago with my 135gal O'Dell. The stand pipe was screwed into the bulkhead and when the power went out from hurricane Opal the overflows slowly drained and overflowed my sump. I used teflon tape and it fixed the problem.

 

If your bulkheads are slip then I would glue a female adapter into it and use teflon on a male adapter thats glued to the stand pipe.

 

If the tank is siphoning back through the return lines you can drill a small hole just below the water level. When the pumps are turned off air will go in the holes and break the siphon. You can also install check valves on the returns but I do not like them myself. They reduce flow, protiens can builds up them causing them not to seal properly and they can make some noise from the water flowing through them.