Ya that's obvious. I should of been more specific .I have a reef in the 55. I dont know if i will venture into sps or not. I mainly keep lps and down. I would like a clam at one point but not sure if any species can go under T5'S.
Biff, has a 90g under T5s and she's got a clam. In a 90 you should be able to keep anything you want under the right T5s. I'm not sure about in a 125 though.
It's not the size of the tank but the depth of the tank.Anything more then 24'' deep then MH or LED maybe a better option.You can still keep corals with deeper tanks using T5 but they will need to be placed according to light needs-SPS top half,LPS middle and softies bottom in general.