ATO Scare need Help

[Amatuer21]

So in the middle of the night i just so happen to hear my ato turn on and top off my system. But it didnt stop!!! I quickly got up to check it and just before my tank started spilling water it stopped. Now i can hear the pump inside the top off reservoir making some kind of noise. It makes a jolt noise every 20seconds or so. Not sure what happened or what the problem is. This is the nano osmolator. It has worked fine for the lastweek no problems. Any thoughts to what this maybe id appreciate it, thanks

[MKReefTank]

Not sure what it might be, but it definitely sounds like you need a new pump. You can probably find a decent pump. I have my ATO connected to an APEX controller just for an extra layer or redundancy. The APEX is programmed to allow the pump to come on at certain times and for a certain amount of time.

[Amatuer21]

Dam i hope its not the pump its brand new. I placed a piece of cardboard between the two magnets and tank glass. I was thinkin it could of possibly been the magnets effecting the float. If it happens again ill rule that out and go with the bad pump. I just hope it doesnt happen when im not around. But im pretty sure the safety feature kicked in after a min or so of it topping off.