Tony wrote: I noticed an anode for swamp coolers advertised on
a web site. Not to ask too stupid a questions, but how
is this installed? Do you throw it into the tub? Or,
do you bury it in the ground (dirt) and run a wire to
to bottom of the cooler?

It's called a "sacrificial" anode, meant to be eaten up by any
galvanic response that would otherwise eat the cooler body.

"Anodes should come into contact with the metal part it will protect,
and the potential of any sacrificial anode needs to be at least 200
milliamps higher than the other metal components". So, I'd connect it
to the cooler body, and let the anode rest in the water. HTH. Tom