Siphon break on a return line?

petedoc · 02/18/2007, 10:32 AM

I am setting up a new 270 gal reef tank and I want to have a return outlet 8" below the the water level. I have a loop of pvc up to the surface and down to the outlet. How do I prevent draining the tank 8" down in the event of a power failure?

dwdenny · 02/18/2007, 10:34 AM

you can drill a small hole just below the water surface (on the pipe going down of course)and that will break the siphon for you.

mta · 02/18/2007, 10:35 AM

Drill a 1/8" hole in the return outlet at the water line.

petedoc · 02/18/2007, 10:46 AM

Sounds great, will the system loose much flow throught the break hole?

AZDesertRat · 02/18/2007, 10:52 AM

You better drill multiple holes the odds of one hole being clear when you depend on it are small. Personally I think your are headed for a catastrophe by having returns that deep.

petedoc · 02/18/2007, 01:10 PM

I think I am confused. This is the line from the sump/return pump to the main tank. I am trying to figure out a plan to have the return outlets well below the water line and not drain the tank into the sump in the event of a power outage. This return line comes from the sump up through the overflow box. Multiple holes might work but a great deal of flow from my pump would be lost in the overflow box.

mta · 02/18/2007, 01:14 PM

The water will take the path of least resistance.The drilled siphon hole will not impact your return flow untill the return pump is off.

hookedonsalt · 02/18/2007, 01:22 PM

Wont a check valve do the same thing? f installed at the bottom of the suction line It will also help in keeping the system primed.

davocean · 02/18/2007, 01:42 PM

Check valves can fail, and siphon breaks can clog.
I keep my lockline returns near the surface, and sump level so it can accept the small amount of overflow.
If you need flow lower, add seio's or tunzes.

AZDesertRat · 02/18/2007, 02:11 PM

Keeping your returns close to the surface and maintaining a sufficient amount of room in your sump for that amount of backflow is the only sure way to avoid backflows/backsiphons. Check valves are mechanical devices and fail even with regular maintenance which no one does no matter how good their intentions are. If you are doing this new design it properly and backflow and flooding is not an issue and you can sleep well at night.

petedoc · 02/18/2007, 03:48 PM

Thanks, I will definitely not use check valves, but I may need to have a portion of flow return near the top, through a lock line or otherwise, to act as a siphon break. The volume of my sump is 110 gallons, but if a the low point of return is 8" below water level in a 270 gal tank and the power fails,,,, well you get the picture.

JTEAGUE · 02/18/2007, 03:50 PM

if you have an overflow box that hoses your return line you can drill the underside of the 90 elbow

02/18/2007, 10:32 AM	#1
petedoc Premium Member Join Date: May 2003 Location: Lewiston Idaho Posts: 1,131	Siphon break on a return line? I am setting up a new 270 gal reef tank and I want to have a return outlet 8" below the the water level. I have a loop of pvc up to the surface and down to the outlet. How do I prevent draining the tank 8" down in the event of a power failure? __________________ Charter member of the Trial and Error Club, when that doesn't work ask the stupid question here on RC to get an intelligent answer. Current Tank Info: 270Reef w/Chrysurus Angel,Vlamingi Tang, Atlantic Blue Tang, Dispar Anthias, Sargassum Trigger

02/18/2007, 10:34 AM	#2
dwdenny Registered Member Join Date: Oct 2004 Location: Edinburg, Texas Posts: 1,369	you can drill a small hole just below the water surface (on the pipe going down of course)and that will break the siphon for you. __________________ "Attitude determine altitude" Visit MAAST.org just click the "Red House" Current Tank Info: 40g Breeder in the works

02/18/2007, 10:46 AM	#4
petedoc Premium Member Join Date: May 2003 Location: Lewiston Idaho Posts: 1,131	Sounds great, will the system loose much flow throught the break hole? __________________ Charter member of the Trial and Error Club, when that doesn't work ask the stupid question here on RC to get an intelligent answer. Current Tank Info: 270Reef w/Chrysurus Angel,Vlamingi Tang, Atlantic Blue Tang, Dispar Anthias, Sargassum Trigger

02/18/2007, 01:10 PM	#6
petedoc Premium Member Join Date: May 2003 Location: Lewiston Idaho Posts: 1,131	I think I am confused. This is the line from the sump/return pump to the main tank. I am trying to figure out a plan to have the return outlets well below the water line and not drain the tank into the sump in the event of a power outage. This return line comes from the sump up through the overflow box. Multiple holes might work but a great deal of flow from my pump would be lost in the overflow box. __________________ Charter member of the Trial and Error Club, when that doesn't work ask the stupid question here on RC to get an intelligent answer. Current Tank Info: 270Reef w/Chrysurus Angel,Vlamingi Tang, Atlantic Blue Tang, Dispar Anthias, Sargassum Trigger

02/18/2007, 01:42 PM	#9
davocean Registered Member Join Date: Nov 2005 Location: San Diego, CA Posts: 14,655	Check valves can fail, and siphon breaks can clog. I keep my lockline returns near the surface, and sump level so it can accept the small amount of overflow. If you need flow lower, add seio's or tunzes. __________________ There's a fine line between owning your tank and your tank owning you! Current Tank Info: SCA 120g RR Starfire, Tunze silence 1073.02 return, 40g sump w/ fuge, SWC Extreme 160 cone skimmer,Geismann reflexx 4xT5, 2x Panorama Pro LED strips, Vortech MP40QD

02/18/2007, 10:35 AM	#3
mta Registered Member Join Date: Mar 2005 Location: yonkers new york Posts: 418	Drill a 1/8" hole in the return outlet at the water line.

02/18/2007, 10:52 AM	#5
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	You better drill multiple holes the odds of one hole being clear when you depend on it are small. Personally I think your are headed for a catastrophe by having returns that deep.

02/18/2007, 01:14 PM	#7
mta Registered Member Join Date: Mar 2005 Location: yonkers new york Posts: 418	The water will take the path of least resistance.The drilled siphon hole will not impact your return flow untill the return pump is off.

02/18/2007, 01:22 PM	#8
hookedonsalt Registered Member Join Date: Jan 2007 Location: Virginia Beach, VA Posts: 16	Wont a check valve do the same thing? f installed at the bottom of the suction line It will also help in keeping the system primed.

02/18/2007, 02:11 PM	#10
AZDesertRat Moved On Join Date: Jan 2002 Location: NW Phoenix Posts: 16,621	Keeping your returns close to the surface and maintaining a sufficient amount of room in your sump for that amount of backflow is the only sure way to avoid backflows/backsiphons. Check valves are mechanical devices and fail even with regular maintenance which no one does no matter how good their intentions are. If you are doing this new design it properly and backflow and flooding is not an issue and you can sleep well at night.

02/18/2007, 03:48 PM	#11
petedoc Premium Member Join Date: May 2003 Location: Lewiston Idaho Posts: 1,131	Thanks, I will definitely not use check valves, but I may need to have a portion of flow return near the top, through a lock line or otherwise, to act as a siphon break. The volume of my sump is 110 gallons, but if a the low point of return is 8" below water level in a 270 gal tank and the power fails,,,, well you get the picture. __________________ Charter member of the Trial and Error Club, when that doesn't work ask the stupid question here on RC to get an intelligent answer. Current Tank Info: 270Reef w/Chrysurus Angel,Vlamingi Tang, Atlantic Blue Tang, Dispar Anthias, Sargassum Trigger

02/18/2007, 03:50 PM	#12
JTEAGUE Registered Member Join Date: Sep 2006 Location: N.C. Posts: 318	if you have an overflow box that hoses your return line you can drill the underside of the 90 elbow