The drinking fountains can cost more than a refridgerator (just got a couple for our church).
For fresh water you could used galvanized or bare steel pipe in the refridgerator; normal water changes will easily take care of the trace of zinc. For a salt tank you need titanium or high nickel (30%+) like Incoloy 825 for tubing. You cannot buy these for less than the price of a chiller (salt).
The idea of a long coil of rigid or flexible plastic tubing will work well with a refridgerator dedicated to "fish"; I mean a small bar or dormitory type refridgerator.
For fresh water you could used galvanized or bare steel pipe in the refridgerator; normal water changes will easily take care of the trace of zinc. For a salt tank you need titanium or high nickel (30%+) like Incoloy 825 for tubing. You cannot buy these for less than the price of a chiller (salt).
The idea of a long coil of rigid or flexible plastic tubing will work well with a refridgerator dedicated to "fish"; I mean a small bar or dormitory type refridgerator.