We have put quite a bit of time and money into the development of the ballasts we are using. The main reasons for failure are heat and arcing in the socket region of the fixture, so here are a couple of things to keep an eye on.
The fixtures need to be installed in an open area that is ventilated. Also make sure that the fan region and opposite side vent are kept clean of dust, debris, fur, etc. Sometimes if the units are mounted in a line they can draw in the warm air from another fixture. As always, make sure the fixtures are not installed inside of canopies. Even ventilated canopies still don't allow the units to dissipate heat through convection cooling using the aluminum housing.
Salt creep and or moisture that gets in and around the socket region can cause a small arc. While this may not be strong enough to damage the lamp or the socket, it can cause the ballast to fail. This is a safeguard of the ballast to ensure that the system shuts down before the worst possibly happens. When installing and changing lamps, it is recommended to put a small amount of conductive silicone (AKA di-electric grease found at most hardware stores) between the holes in the lamp socket. This adds an insulative barrier that will prevent salt creep and moisture from getting into the pin area where an arc can occur. This is a possibility why the ballasts are failing.
We have also provided a link to the eNewsletter for monthly maintenance tips that will also help prolong the life of your fixture.
http://current-usa.com/wavelength.html