Ok...
went to the gym and worked out my stress.
So this is what I am thinking...
When I was able to get it to activate the pump by removing the sensor from the water, this told me it's not the sensor - it's the overflow box and pump. I think what's happening is the pump is not removing water fast enough.
I also consider the box and pump to be the weak link in general. Because of the mount (had to use suction cups) I don't think it's permanent by any means and can come loose. Problem 1.
Problem 2 is that the little 70gph pump inside the box can become clogged easily preventing the water from lowering below the sensor.
(A related problem is that the box is rather small and the pump had to go in sideways and sits up against the sensor more than I would like. Plus, being sideways, it sucks in air easier as the intake is now vertical and not horizontal.)
What I am thinking about now is...
can I flip the sensor over so that it points up? This effectively raise the sensor quite a bit and I bet it would work. However the instructions say to point it down. Why is that?
If that isn't really an option, can I ditch the box and pump all together and mount the sensor with some zip ties or something on the side of a filter tube in my tank? I would then mount the high water sensor somewhere as well.
I would feel a lot better about it doing this as it would no longer have to rely on the overflow pump and it gets the box out of my tank.
Thoughts?