A pressure switch is set so that it will activate at the level of the tide that the customer wants and can be adjusted. The way it works is as the tide rises it increases the pressure in the pipe to our pressure set point. When this pressure is hit, a pump turns on and draws the fluid up the pipe until either a timer has been limited or until the tide goes down and relieves the pressure on the momentary contact pressure switch. It is easy to protect the switch on top, the only thing that goes into the saltwater is a pipe and the depth of the tide that the you want to set it at is adjustable. The best thing is that it works really well and the investment in the pressure switch in minimal.