Part 4 - The 'Switch Tree'

The water storage tank currently has three switches -- they are submersible polypropylene 'GEMS' sensors, which originally were sold by Digikey (http://www.digikey.com). I constructed the 'tree' with a length of PVC, a number of  1/2" threaded T's, and a 'flange' at the top, mounted through the tank lid.

TOP of Tank detail

Not a very good view, but looking into the tank at the switch tree

I initially was going to use a small Microchip PIC microcontroller to control the various modes, monitor switch levels, etc. but thought that the future mainenance aspect might be difficult -- what if everything was working great for a few years, but then needed to replace the controller due to a component failure or lightning? Would I be able to program the parts in the same way, etc?

So instead, just used relay logic to sequence the switching between the tanks....

Part 5 - Relay Switching