Osmolator triggering every minute or so

[Fishmommy]

I just installed an Osmolator Universal on my 135g system. The sensor is in the sump return chamber. The water level is well above the baffles at the happy spot. The unit is satisfied at level (green) for about a minute at a time but then triggers too low (yellow) and runs the pump. Is my system really evaporating that fast? It's been doing this for many hours now since I installed it. Is there a way to widen the hysteresis band?
Thanks

update.....my output tube was below the water level and above the reservoir. I believe the pump was back siphoning tank water into the ATO back and forth, causing the problem. Does this sound right to you? I cut the tube above water level and the unit seems happy. Let me know if this was a possibility. I guess I should dump out my ATO reservoir now

 

[rvitko]

Yes, I was just going to say it sounds like a back siphon.

 

[Fishmommy]

woot! Thanks for the validation. Dumb mistake.

 

[tobey]

I'm having a very similar problem but my output hose is above the water line. My ato was working great for the first week. Then today it started acting weird. It turns itself on an off randomly an over filled my tank with ro (sorry for the hijack fishmommy)