Can't stop the siphon!

Seajuice · 05/26/2006, 09:34 PM

I have an auto top off system with a float valve in the sump and a pump in a 25 gal. vat. The system works well but when the vat is full and the pump goes off the water still flows into my sump. The pump is pretty low into the vat and I have put a couple of coils in the tubing. I'm sure there is a good solution but I can't seem to come up with it. I thought of a check valve but that just prevents flow in the reverse direction.
Very frustrating, thanks in advance for anyones help.
Feeling very stupid that I can't think of a solution!

artful-dodger · 05/26/2006, 09:39 PM

Is your vat above the level of the sump? Sounds like the problem is only when the vat is full (water level at its highest) and gravity is pulling water through the non-spinning pump impeller.

Can you raise the level in the sump to the height of the vat? Can you raise the entire sump up enough? Lower the max volume in the vat? Perhaps a different design of pump that won't backflow? A check valve might do what you need, though. There are different designs, but one with a strong enough spring might still close with just gravity's force.

Seajuice · 05/26/2006, 09:42 PM

The vat is at the same level as the sump and yes it only occurs when the vat is full. Gravity is pulling it through my MJ1200. (I think its a 1200)

artful-dodger · 05/26/2006, 09:54 PM

another idea...move the "drip" end of the top-off line to above the sump (to a height above the top of the storage vat). As long as it is securely positioned in the stand and doesn't splash a lot it would break the flow. Perhaps a smaller powerhead would reduce the splash factor.

One more...what if the supply line had a tee above the water level of the vat...the tee going to a second line with a check valve turned backwards so that under pressure it doesn't flow but air can backflow. (Might be risky if that checkvalve didn't allow the airflow.)

Okay, one more idea...use the high tee again, but take the second output and route it back to the very top of the vat. That would break the gravity feed but would cut the flow rate to the sump as it recirculated some water back to the storage vat...shouldn't be a problem for topoff.

Seajuice · 05/26/2006, 10:31 PM

I like the T idea just above the sump. Why use a check valve at all. just have an open T to introduce air. I'll try and report back.

affan · 05/26/2006, 10:31 PM

Can't stop! Won't stop!

artful-dodger · 05/27/2006, 01:15 PM

The idea of the tee and check valve was to keep water from blowing down that line when the pump is engaged.

Actually, I think the final suggestion would be the safest...rerouting a tee'd line back to the top of the vat leaves nothing open to the air that could create a mess.

rich415 · 05/28/2006, 01:08 AM

I have my resevoir about 3 feet above my sump. I stopped the syphoning by puncturing a small hole in the side of the tubing leading from the pump into the sump. I inserted airline tubing into the hole and make sure it is above the water surface in the resevoir. Every time the pump stops the airline tubing sucks air and breaks the syphon. Just make sure it stays above the water line. Just like back syphon holes cut into the return line in the main tank.

Saltz Creep · 05/28/2006, 06:50 AM

Smartful-dodger has the easiet solution. Just secure the output end of your hose above the level of your topoff reservoir. It shouldn't splash much if you allow the water to run down the side. The anti-siphon hole is an OK idea too as long as you don't get a thin stream of water shooting where you don't want it.

rdmpe · 05/28/2006, 11:04 AM

Put the end of the pump output tube up above the top of the resevoir. Have it flow into a slightly larger piece of tubing that returns down into your sump. The tubing into the sump needs to be large enough that it doesn't seal up with the pump output tubing.

05/26/2006, 09:34 PM	#1
Seajuice Registered Member Join Date: Dec 2005 Location: Plymouth, MA Posts: 146	Can't stop the siphon! I have an auto top off system with a float valve in the sump and a pump in a 25 gal. vat. The system works well but when the vat is full and the pump goes off the water still flows into my sump. The pump is pretty low into the vat and I have put a couple of coils in the tubing. I'm sure there is a good solution but I can't seem to come up with it. I thought of a check valve but that just prevents flow in the reverse direction. Very frustrating, thanks in advance for anyones help. Feeling very stupid that I can't think of a solution!

05/26/2006, 09:39 PM	#2
artful-dodger Registered Member Join Date: May 2004 Location: Highlands Ranch, Colorado Posts: 3,011	Is your vat above the level of the sump? Sounds like the problem is only when the vat is full (water level at its highest) and gravity is pulling water through the non-spinning pump impeller. Can you raise the level in the sump to the height of the vat? Can you raise the entire sump up enough? Lower the max volume in the vat? Perhaps a different design of pump that won't backflow? A check valve might do what you need, though. There are different designs, but one with a strong enough spring might still close with just gravity's force. __________________ "In matters of style, swim with the current; in matters of principle, stand like a rock." -- Thomas Jefferson Current Tank Info: 140g RR Oceanic "Ultimate" mixed reef, 37g softies, 40g RBTA tank, 65g FOWLR, 40g breeder frag, and (of course) a 29g QT! ...next up is a 240g! (Gotta go to K-Mart and buy a life...)

05/26/2006, 09:54 PM	#4
artful-dodger Registered Member Join Date: May 2004 Location: Highlands Ranch, Colorado Posts: 3,011	another idea...move the "drip" end of the top-off line to above the sump (to a height above the top of the storage vat). As long as it is securely positioned in the stand and doesn't splash a lot it would break the flow. Perhaps a smaller powerhead would reduce the splash factor. One more...what if the supply line had a tee above the water level of the vat...the tee going to a second line with a check valve turned backwards so that under pressure it doesn't flow but air can backflow. (Might be risky if that checkvalve didn't allow the airflow.) Okay, one more idea...use the high tee again, but take the second output and route it back to the very top of the vat. That would break the gravity feed but would cut the flow rate to the sump as it recirculated some water back to the storage vat...shouldn't be a problem for topoff. __________________ "In matters of style, swim with the current; in matters of principle, stand like a rock." -- Thomas Jefferson Current Tank Info: 140g RR Oceanic "Ultimate" mixed reef, 37g softies, 40g RBTA tank, 65g FOWLR, 40g breeder frag, and (of course) a 29g QT! ...next up is a 240g! (Gotta go to K-Mart and buy a life...)

05/27/2006, 01:15 PM	#7
artful-dodger Registered Member Join Date: May 2004 Location: Highlands Ranch, Colorado Posts: 3,011	The idea of the tee and check valve was to keep water from blowing down that line when the pump is engaged. Actually, I think the final suggestion would be the safest...rerouting a tee'd line back to the top of the vat leaves nothing open to the air that could create a mess. __________________ "In matters of style, swim with the current; in matters of principle, stand like a rock." -- Thomas Jefferson Current Tank Info: 140g RR Oceanic "Ultimate" mixed reef, 37g softies, 40g RBTA tank, 65g FOWLR, 40g breeder frag, and (of course) a 29g QT! ...next up is a 240g! (Gotta go to K-Mart and buy a life...)

05/28/2006, 06:50 AM	#9
Saltz Creep Registered Member Join Date: Jul 2004 Location: Hickville, FL Posts: 3,728	Smartful-dodger has the easiet solution. Just secure the output end of your hose above the level of your topoff reservoir. It shouldn't splash much if you allow the water to run down the side. The anti-siphon hole is an OK idea too as long as you don't get a thin stream of water shooting where you don't want it. __________________ veni, vidi, vici piscis merda

05/26/2006, 09:42 PM	#3
Seajuice Registered Member Join Date: Dec 2005 Location: Plymouth, MA Posts: 146	The vat is at the same level as the sump and yes it only occurs when the vat is full. Gravity is pulling it through my MJ1200. (I think its a 1200)

05/26/2006, 10:31 PM	#5
Seajuice Registered Member Join Date: Dec 2005 Location: Plymouth, MA Posts: 146	I like the T idea just above the sump. Why use a check valve at all. just have an open T to introduce air. I'll try and report back.

05/26/2006, 10:31 PM	#6
affan Moved On Join Date: Jan 2006 Location: From NYC, currently serving time in Hattiesburg, MS Posts: 1,125	Can't stop! Won't stop!

05/28/2006, 01:08 AM	#8
rich415 Registered Member Join Date: Jun 2005 Location: San Francisco, CA Posts: 172	I have my resevoir about 3 feet above my sump. I stopped the syphoning by puncturing a small hole in the side of the tubing leading from the pump into the sump. I inserted airline tubing into the hole and make sure it is above the water surface in the resevoir. Every time the pump stops the airline tubing sucks air and breaks the syphon. Just make sure it stays above the water line. Just like back syphon holes cut into the return line in the main tank.

05/28/2006, 11:04 AM	#10
rdmpe Registered Member Join Date: Apr 2003 Location: Central Florida Posts: 3,737	Put the end of the pump output tube up above the top of the resevoir. Have it flow into a slightly larger piece of tubing that returns down into your sump. The tubing into the sump needs to be large enough that it doesn't seal up with the pump output tubing.