Anything you want because you have a shallow tank. I have been able to keep SPS under CF's, but I do it in a 29 with one 96w power quad. Which I have to change out every 8 to 9 months. ($45) In your case you will have 8 x $30 = $240 every 8 to 9 months. That will get expensive. You might want to switch to MH or T5HO because of the replacement cost. If you are just wanting to keep softies or LPS you should be fine. Just keep 50% of your lamps true Actinics. Good luck on what ever you decide.