I have a 90 bowfront and it is 29 tall t5 barely did the trick , so went from 6 36" t5s to 2 48 " t5s, 2 250 w mh and 2 110 w vho. my personal opinion is if you are going that tall (31") you will need more than t5s if you are doing sps. If you are really just wanting a bigger tank for sps and fish depending on howmuch you have in the stand maybe just bite the bullet and go bigger... Start fresh. look at the 150 display at aquatech its the perfect tank. I'm just saying this because I would hate to get done with a project like that and not be completely happy with the outcome.