Osmolator overfilling

[Humongous]

My parents have an osmolator with a new pump installed 2-3weeks ago. The problem I'm having with it is that it keeps filling past the sensor, past the top of the sensor to be exact. It's almost as if there is a siphon still pulling water. I've tried routing the fill hose for them a couple of different ways but it's still happening. The sensor is clean and the rest of the unit seems to be operating fine. Any suggestions?

Thanks

 

[rvitko]

The reservoir needs to be below the tank and the water should be pumped up to the aquarium, otherwise the pump will shut off but water will continue to siphon.