Problem with ATO

[MrsBugmaster]

I have the Tunze Osmolator Universal 3155 Auto Top Off.The past 3 days now when I go look at my tank the water level is low and the top off controller "too low" is light up. I unplug it and plug it back and in it starts working and fills the sump back up to normal. So the pump is pumping again. Next day same thing. Is the problem with the pump or the controller?

 

[rvitko]

Too low means generally the pump has timed out. It is a 10 minute time limit. The pump could be failing (they typically need to be replaced after 2-3 years), the pump could be airlocked and unable to pump (tip it upside down to purge trapped air) or the water level could actually be very low, 10 minutes is equal to about 2 gallons of water, you can vary the pump speed and depending on head pressure it is 1-3 gallons. If too low comes on quickly, within about a minute, the controller was erased by harsh on and off switching (usually when connected to another controller) or by a power surge, we can reprogram the settings if you send it in. If too low is on with too high, this is the water damage indicator.