Quote Originally Posted by Phydeauxman View Post
last week we discovered that the ozonator does not appear to be working
I wouldn't worry about it . . . even when they 'work', they don't really work. I'm guessing that no one ever explained to you that ozone and chlorine engage in a mutual destruction reaction.? And, on a plaster pool, a 'working' ozonator is a constant source of aeration, which makes it more difficult to maintain your pH and alkalinity levels.

The best thing you can do is simply remove the unit, and especially, any venturi which wastes LOTS of pump effort by restricting water flow. Second best is to cut off or plug air flow through the unit, so it can't aerate your pool, and to open the venturi bypass -- if there is one -- fully.

Ozonators can have a useful function on spas, and maybe, indoor pools. Currently, we're not aware of ANY useful function an American style ozonator can have on an outdoor pool.