ATO freshwater container?

[monza]

It's always a good safety feature to have a smallish fresh water top off container, say a five gallon bucket. That way if some thing fails in the auto top system and it sticks on or a syphon is created you don't flood your tank with to much fresh water. Another float switch/ timer can feed the five gallon from a larger storage container.
Very important it can't continue a syphon for sure.