Why would my ATO not turn off and cause this overflow of water?

[Leon Gorani]

so i have my tank set on the floor, temporarily, with a bucket of water next to it for my ato and i have the ato sensor just under the rim, inside of the tank. i just got an alarm that it had overflown onto the floor. i got up and cleaned it and i saw that there was a snail ontop of the ato sensor. i double checked to make sure there was no siphon happening and even left a space between the water level and the end of the ato tube so it wouldn’t touch. my ato tube was actually draped above my light, but took it off when i got up to clean. this just happened at 4 am.
Would the snail just sitting on the ato sensor activate it and overflow the tank? i am really surprised but glad my water alarm on the floor went off. the lowe’s bucket is my ato bucket and please ignore the towel and other stuff, but that is what my set up looks like.

 

[blaxsun]

Yep, snails can definitely trigger stuff.

 

[Icryhard]

You can buy an ATO which disables itself if the output of water is more than 10% of the previous sessions. It then triggers an alarm.

 

[Murphs_reef]

Asterina stars set mine off all the time... Pain in the ...

 

[BaliReefBox]

Asterina stars set mine off all the time... Pain in the ...

Chocolate starfish!

 

[reveriesh]

Chocolate starfish!

I just literally laughed out loud!!

 

[Aquaddictorbj4]

For Optical Sensor, the direct light issue will might also cause the sensor malfunction.
Maybe you can try to move the sensor away from the direct light.

 

[ptrick21186]

Definitely the snail