Not all stainless is salt water safe in fact, I wouldn't use anything that has a fully body of stainless steel exposed to salt water. I'd bet that thing would corrode pretty darn quick if continually exposed to salt water.
If you want a good UV, get an Aqua UV or Emperor Aquatics. Both are designed for salt water use, offer easy serviceability and have good ballasts that won't fail on you a year down the road.