True. But float switches have a funny way of failing, and they are eyesores. I don't really want a float switch in my display, fuge, frag tank and sump. Probably the failsafe would be dual floats in all the tanks AND floor sensors but then how do you hook all of that up to the return pump?
I like the relatively low cost of these sensors. What I can't figure is how to link 2 together so that I can have either sensor shut off the return pump (if I had one on the floor upstairs vs. display overflow and one downstairs vs. frag/fuge overflow.)