Osmolator Problem

[68sting]

I picked up a tank that came with an Osmolator. Its been giving me a problem about once a day. I'll hear the alarm and sure enough the sensor didn't kick off the pump and the back up sensor had to turn it off. The sensor appears clean. Any idea why it doesn't want to work occasionally?

 

[rvitko]

Things I would check to start-

1) Does the water stop with the float valve or is the water also above the float- this could indicate a siphon and the water level in the reservoir is above the end of the hose so water siphons until the water level in the reservoir is equal to the height of the end of the hose.

2) Does this error coincide with something turning on, perhaps a ballast or light fixture?