Well I am currently going throught this and I have read so much that I am worse off than I was before the research. From what I have read it is split 50/50 if a clam can be kept under T5 ho. I would say yes as long as it is quality and maybe if you go with a Dersa since it requires medium light. They say Nova is a good quality but everyone prodes on the Tek but you pay for it. I say if you tank is 18" or less deep just T5 should be fine if you have good reflectors. But if it is deeper I would for sure go MH.