Back Siphoning

[brians_224]

Can you help?

I'm having real back siphoning problems on my return line. I ran my returns up from my sump over the side of my built-in corner overflow back to the bottom of my tank and then I tee off to two different outputs. The problem is that when i test the fail safe methods, they fail. B/C my returns run to the bottom of my tank, there is a ton of h20o that could be potentially back siphoned. So I added more holes, it's much better but still not 100% effective, in addition I'm losing a ton of output through these four holes.

I drilled 4 3/16" holes in my return line.

Any help would be really appreciated! Are there other options instead of these holes?

[Hobster]

The water level will have to go below a hole before it "breaks" a siphon. Did you drill any holes about 1" from the top water line?

[Scuba_Dave]

I drill 1/8" holes just above the water line, has worked fine so far

[brians_224]

I used larger holes than 1/8" I'm using a diy durso, I placed the holes about 1 inch below the T.

What i think is happening is that these siphon break holes are actually making matters worse. They are dumping water into my over flow not allowing the siphon to break in my durso.

I'll try smaller holes higher on the pipe.

Thanks

[Bamm Bamm]

Install a check valve on your return line and you won't have to worry about it.. All my returns are under water on my new tank for Astetics(sp?) so i got a clear and cleanable check valve for like $20 from marinedepot.. You can buy non servicable ones from HD and Lowes but they look like they would limit flow alot..

[Glass World]

I'm confused here Brian, can you draw a diagram of what you're trying to accomplish? You mentioned using a DIY durso and I think you're drilling anti-syphon holes in that? You shouldn't need any anti-syphon holes in your drain. A correctly setup overflow should take care of itself in a power failure.

You also said (I think) that you're running your return lines through your overflow to the bottom of the tank, then out from there. If this is what you're doing then you need to be careful to make sure that there is a good seal around where the returns come out of the overflow. The overflow box in the tank needs to be completely sealed off from the rest of the aquarium water (except for the top... which the water flows over). If water is leaking in around the pipes or tubes at the bottom of the overflow then this could be part of your problem too.

Also, be aware that it does take a little while for all the water to settle down in a power failure. Depending on the size of your tank and the placement of the syphon breaks and all it's not uncommon for 5 to 10 gallons or even more to flow into your sump before the syphon breaks and water stops. You need to make sure that you have this much room in your sump at all times or the sump will overflow.

If your system is set up correctly the sump should not be all the way full when the system is running. When the power fails the drain should continue draining until the water level falls to the bottom of the teeth in your overflow. The return line will start syphoning water to the sump as soon as the power fails and will continue to do so until the syphon breaks are above the water line and can let in enough air to stop the syphon. Until all this happens water will be continuing to flow into your sump. Depending on the size of your return and how far under the waterline the syphon breaks are it may take it a few minutes to completely stop.

HTH

[Glass World]

[thedogofwar]

yeah, what Glass World said, you're drilling the wrong lines.