To keep this from happening again, be sure that air is flowing through the whole system. When I see one come in for repair that matches your description, I can count on the tubing being bad somewhere between the ozone generator and the ozone injector. A bad check valve, or just bad tubing can cause the air to stop flowing, and that will allow the ozone to go to work on the generator. Be sure to put in all new tubing and a new check valve when you install - the injector is usually fine to reuse but be sure it is nice and clean inside. Stay with the spring clamps! Automotive screw clamps don't work well on vinyl tubing.
We keep a few FWIII systems on the shelf, one or two which I have refurbished, too. I find I can usually sell them for right around the same or less than the Del units, but your price may vary. Ask your dealer for his best over-the-counter price and install it yourself.
The JED units are very inexpensive, but you have to replace them every year - some may go two years. The Eclipse unit from Del has a replacement chip which goes 9000 hours (fourteen months, approx) before IT needs to be replaced. If you buy an Eclipse, buy the "Spa Renewal Kit" at the same time, and put it on the shelf. Saves shipping, and you will need it in one to two years.
The Del MD50 is very much the same as the FWIII. You have to be sure to order it with the correct power cord. Goes a long time - IF you keep the air moving through it...