Yes. I use both floats in the sump. Bottom one as normal. The other one that usually goes in the top off container, is flipped over in the sump above the other one.
The bottom one turns the pump on and off with normal use.
The top one that's flipped is the emergency. If the water gets to that one, the pump is cut off. (The jbj thinks that the top off container has run dry.)
This is on mode A
Well my reef keeper has its own floats and they keep my pumps from running dry, I was thinking this could be potentially used for making tides in an aquarium maybe? Would be pretty cool!