Auto Top Off Issue

[Editour2]

I'm trying to connect my ATO to my 35 gal fresh water reserve tank. I have the top off pump connected to the ATO and the ATO to my RKL (redundancy). I set the RKL to only turn on the ATO 2ce a day for 1 minute. While testing this out...once the water drops below the sensor level in the sump the pump turns on...then when the water reaches it's proper level (via the sensor) the pump shuts off....PROBLEM....a siphon effect kicks in and does NOT stop the water from continuing to fill my sump. I have to pull the hose out of the reserve tank to stop it. Obviously I don't want to come home with the sump filled with fresh water by emptying the 35 gals in my reserve tank.
IS THIS BECAUSE MY RESERVE TANK IS APPROXIMATELY 3 FEET ABOVE THE SUMP THAT IT IS CREATING A SIPHON EFFECT, (it is the top brute can in the pic)? DOES THE RESERVE TOP OFF WATER HAVE to be below the sump? Which of couse means I can't use this method.....AND I'll need another reserve tank on the floor for my top off. See pics below and thanks for your help.....

 

[thavngr98]

Yes. I had the same problem. With my setup I was able to my my tubing from the reservoir to my overflow keeping the float switch in the sump. Now my reservoir is about even with my DT. The other thing you could do which I may eventually do is run a 1/4 in tube from fresh water container to a new container level with the sump (floor?) and put a float valve in the new reservoir so it stops filling when level is achieved. Then put ATO tube in there. Hope that helped.

 

[weezyfella]

The issues you are having of back siphoning is because the height is higher then your sump. You'll need a check valve to allow only one direction flow or a some type of vacuum breaker. Since its is RODI water you won't have any issues with salt build up, potentially blocking the check valve.

Another way would be to make a U but upside down, like the u-tube for overflows. That way water has to travel up then down, creating an air gap, this should prevent water from flowing once it stops. Hope that makes sense.

 

[fishome25]

I solved this problem by drilling a hole in the pipe in the barrel. it would break the siphon.

 

[WallysWorld]

Frank,

Just run a 3/4 inch pvc pipe along the wall higher than the supply tank. Run the other end into the sump. Then take the 1/4 or 1/8 inch tubing coming from the ATO pump and run it into the top of the 3/4 inch pipe. The key here is to have the open end of the 1/4 inch tube higher than the supply water level, like Tom said you need an air gap to break the syphon. I can pop over Saturday or Sunday for a better explanation, let me know.

It's an easy fix.

 

[mbg75]

Wally hit it perfect. Air gap at highest point