I assume these are normal output T5s. you would want at least 54wx2 of T5 HO (high output) T5s for any reef (assuming this is a standard sized 55g). 3 or 4 tubes of normal output flourescents might do the trick for low light soft corals (I specified low light because many soft corals such as several popular leathers and zoanthid arent low light and low flow corals and do so much better under high lighting).