Back siphon

[liverock27]

What is the best way to stop my return from back siphoning into my sump?
My return is loc-line split into two returns and right now when I shut off the power it is returning water to the sump until it is lower than the loc-line.
I have read about drilling holes into the loc-line, but don't know where I should drill those holes.
Thanks yall.

 

[fishhook]

You want to bore the hole just below where the surface of the water is when the pumps are running, that way the siphon breaks before the overflow get the water drained to the low level.
The idea is to have the hole just below the surface of the water when the pump is running but not so low that it would drain below the level that the overflow is going to drain to. Also, you want it under water while running to help keep down the salt creep.

Hope that helps.

Greg

 

[liverock27]

Thanks Greg, that does help a lot. Now I just need to figure out how to do that. Could I drill the holes on the loc-line itself? I have one return pointing towards the surface, but other than that the return itself sits below the overflow.

 

[jade76]

drew, drilling into the locline would be fine. you want to drill the hole hole facing down of course because water will spray through this hole. IMO I would drill two 1/8" holes at referance to 5 & 7 O' clock, only about 1/4" under the surface of the water.

 

[liverock27]

Thanks J, I got the drill out now. This is the last thing I need to do before I get your old system up and running.

 

[linda lee]

Rememeber -- siphon holes get plugged easily so you need to use a toothpick, skewer or whatever once a month or so to make sure there's no blockage.

 

[liverock27]

Linda Lee;179521 wrote: Rememeber -- siphon holes get plugged easily so you need to use a toothpick, skewer or whatever once a month or so to make sure there's no blockage.

Thanks for the hint Linda Lee.

 

[liverock27]

Thanks Barbara for the suggestion. I am going to try that out before I start drilling.

 

[johnr2604]

Barbara;179624 wrote: Drew, I have seen this technique on somebody's website. It might have been Marc Levinson's.

For me, I do it the old fashioned way. One of my 2 lockline returns is used to agitate the surface water and the hole is just below the surface. When I turn off the pump to feed the tank, the siphon breaks almost right away b/c that one lockline return immediately gets air. I don't have to drill any holes and my surface water stays agitated too.

Thats how I do it. I just keep the reurns up high and it just siphons out untill it breaks the surface.

 

[gwhiz]

I've got four loc line returns and one or two of them are set to agitate the surface while two are deeper. I've got them all drilled (1/4" hole in the side of the locline just below the normal surface) so that a.) I can reposition them if I want and b.) if I move them all lower (accidentally or on purpose) I still have a siphon break.

...and if you're thinking that it won't happen to you...it just did to me--I added some frags and pushed the locline out of the way...and forgot to reset it. When I turned the pumps off to feed I came within an inch of flooding the sump. If I hadn't drilled the hole......

 

[liverock27]

Thanks yall for the pics and suggestions. I moved the loc-line to the top and it worked perfect when I turned off the power.

 

[liverock27]

Gwhiz;179745 wrote: I've got four loc line returns and one or two of them are set to agitate the surface while two are deeper. I've got them all drilled (1/4" hole in the side of the locline just below the normal surface) so that a.) I can reposition them if I want and b.) if I move them all lower (accidentally or on purpose) I still have a siphon break.

...and if you're thinking that it won't happen to you...it just did to me--I added some frags and pushed the locline out of the way...and forgot to reset it. When I turned the pumps off to feed I came within an inch of flooding the sump. If I hadn't drilled the hole......

Thanks for the heads up George. I will make sure to drill the holes for backup.