Bean animal siphon question

[BChen7106]

I have a beananimal overflow set up in an external overflow box.


I need some plumbing advice. I recently discovered that when the power to my return pump cuts out, a ton of water siphons back into my sump. I think it's more than my sump can hold.


I think the reason is that my overflow box is quite large so all the water in the overflow box back flows until the siphon breaks. So my thought is to drill a hole in the PVC pipe just below the water line. So when the pump cuts out it just drains until that hole comes above the water line and breaks the siphon.


When the pump is on since the hole is below the water line it should still maintain a siphon. I drew out a rough sketch attached.


The sketch shows the siphon line (the other 2 drains aren't included). The dashed line represents the water level required to break the siphon as it is now. The x'ed line is the water level to break the siphon if I drill a hole in the PVC drain.


Thoughts? Specifically when I turn the pump back on, do you think it could spontaneously reform the siphon? Problem would be that air will get sucked down the new hole until it becomes submerged below the water line.

 

[NobleSun27]

Seems like that would work ok but like you said you might not be able to just turn on the pump and restart a siphon. What about the other drains could you just raise them so not as much water would leave the overflow or maybe create a baffle of some sort to hold some water so not as much would drain into the sump. Sorry just giving out a few ideas its hard to say without a better view of your overflow box. Can you take a pic?

 

[saltyhog]

That would only stop a very small volume of water wouldn't it? Most of my water that falls in the DT with the pump off comes from back siphoning of the return nozzles not the overflow box. The return nozzles should be just below the surface of the water enough to keep from splashing and causing salt creep.

 

[NobleSun27]

Yeah my return also siphons back to my sump but I use my return only for surface agitation so its kinda pointed up so it only siphons for a few seconds before it stops

 

[BChen7106]

Thanks for the replies.

My return nozzles are indeed just above the water surface in the dt. They only siphon a little bit of water. Because my external overflow box is so large, it siphons a good 2-3 gallons before the siphon breaks.
At this point I can't really change the height of the siphons or I would just lower them all so that there is less overall water in the overflow box. Hence my idea to drill the hole in the PVC.

I guess worse comes to worse I can always put a finger over the hole when the pump goes back on until the siphon forms.

 

[mfinn]

If 2-3 gallons of water is enough to create a flood from water going back to your sump when the pump is off, then I would suggest either going with a taller sump, or going with a lower water level in the sump.