Just thinking about ATO floats

[Chris_150G]

I have been worrying about the possibility of a flood caused by my auto top off float. I have a pure water club ATO float in my sump/refugiums pump compartment.

Recently my filter sock got dirty enough to restrict the flow from the DT into the sump. This caused water to back up in the DT and get low in the pump compartment of the sump. This could also occur if something were to obstruct and restrict flow thru the overflow box. (like algae over growth)

The problem is that the ATO reacted by adding water which then raised the DT water level even higher. It didn't flood, but could it?

 

[VAreef]

You need a float switch to shut your return pump off if your DT level gets to high. I have overflowed a tank before due to a broken syphon so something to protect that from happening is a good idea. They make some commercial products that can do this or if your inclined electrically I can tell you how to make one.

 

[Chris_150G]

I'm pretty inclined. How does it work?