Hi I was wondering if anyone is aware of a study or rating that has been done on mercury vapor bulbs. It looks like many manufactures are now making them and I don't know if one is better than another. I have heard good things about mega rays, however some of the other brands are available closer to home. I guess the 2 main issues are how long do each of the bulbs provide useable u. v. and at what level. Any info or personal experience with these bulbs would be much appreciated. Thanks in advance