I bought two of them for my 55 gal 48" standard tank. They are awsome. I know where you got 'em, (PW). They have some great prices. I have them about 3 inches above my glass top mounted in my canopy. In fact, I may get one more. Right now they are the 50/50 bulbs and I have a torch coral, long tent. anemone, frogspawn, leather corals, mushrooms etc.
They really work great. DO IT.