I'm planning to install a float switch in 20 gallon tank to store the RO/Di water. To avoid having the RO/Di system turning on and off for small volumes of water, I was hoping to select a switch that would have a long throw arm to allow a 6" to 8" swing in the water level between cycles. I was also thinking of installing two switches in series (reliablilty issue) as well as an overflow fitting (plumbed to a drain) to divert a spill. Can anyone tell me of such a switch & is it reliable? Thanks, Jim