Aqualifter question

[macky]

I recently bought an aqualifter to use as a top off pump. I have a pail holding fresh water on the floor and the pump is located at a height higher than the water level of my sump. One of the lines is in the pail of water and the other is in the sump. The aqualifter comes on twice a day with a timer and has worked fine for 3 weeks. Yesterday I found it siphoning water from the sump to the fresh water pail when it was turned off. What am I doing wrong?
Thanks

[Delphinus]

It doesn't have a mechanism to stop flow when it's off. If both tubes are under the water line and you get a continuous slug of water from one end to the other then when the pump is off, water is going to siphon from the higher water level to the lower (ie., either forward or backwards) regardless of where the pump itself is situated. You should have your output tube in the air higher than the source water and dripping into the sump. That way when the pump is off, the water in the lines falls back into the FW reservoir, the lines fill with air and the siphon breaks. It means it has to reprime each time but I think the Aqualifter can handle self-priming. If not, then you could try a check valve.

HTH!

[Stones]

Make sure the tube going into your sump is above the water level so that a siphon can not start. I'm assuming that the tube was submerged in your sump at a level higher than the level of the tube submerged in your top off pail. If it isn't possible to have the tube going into your sump above the water level, drill a small hole in the tubing above the water level to act as a siphon break.

[macky]

The line in the sump is under water. I will fix that. Thanks for the replies.