Ok, I'm hoping to upgrade my lighting on this to a dual 13watt PC retrofit unit. Nothing else will fit its trapezoid shaped top which goes from a width of 13" down to 12" and halides are not an option. What I'd like to know is if anyone has kept any kind of corals successfully under only 26watts of lighting and what specific species did best for you. I know I may have to settle for a fowlr tank only, but, if possible, I'd like to try some corals. I know most mushrooms are ok, but what else? Are any of the lps suitable for low light setups?