MH. I would look at the 150w hqi pendant made by coralife. They are a good set up. They do not need a hood or anything. They look better than a standard pfo type pendant. Some people will say that a 150 is not enough, however the 150 hqi's put out a similar par to that of a 175w se. I think that should be fine for a 55. Now having said all of that. I think that t5's could possibly be sufficient, however you would have to have an 8 bulb system and the width of the fixture over a 55 would be overwhelming. Also I don't have any experience with t5's also. when pc's came out they were the toast of the town. After a while we collectively realized they really aren't that good for our use.