I have used the kent float (non electrical) for years without a problem, I feed mine off of my RO unit directly to it. The key is to set the float valve so the water inlet is above the water level so no algae grows on it. Not to mention the fresh water being forced through keeps salt creep off. The only time it did malfunction was my own fault for leaving the pumps power cable resting on top of the float.

How many times has your toilet tank overflowed because the mechanical float went bad?