Are there replacement tanks available? It's kind of a fair bet that the bottom of the tank that blew the hole is somewhat uniformly corroded.

Myk Rian

The switch you're referring to is alternating contactor switch. It does 1 then 2, then 1 then 2, and if the demand exceeds supply it allows both to run and stops on the last run sequenced compressor. In this specific case I think both would be running all the time, and the duty cycle time and wear would be a non issue. For a permanent installation it is a control element that you would want to incorporate.