Thanks for the tips! I have the lights sitting on a glass lid. I know with my reefs I'd not use glass due to absobtion, however in this case it might be a good thing. The housing as a seperatate switch for the center bulb so that should give me some good control. Yhe other question is whether its permissible to have two shorter photoperiods in a day vs. One 8-12 hour period? It would be nice to have lights morning and evening without keeping them on for the full 15-16 hours which would clearly be a bad idea.