Well Tank question

[Sdgiant]

We have a Artesian well which flows to a holding tank and old galvanized water tank in our basement.. on the top of the tank there was a two piece plastic part that would stop the water when the tank was full.. I cannot find another one of these because I believe it to be antique or vintage.. do they make anything nowadays that would do the same thing? Any help would be very greatly appreciated!

 

[Valveman]

A picture would help. But I think you may have an air release valve. A float valve like in a toilet tank only larger would also work.