Ample light is mandatory for the success of any thriving aquarium.....nano size upwards. Sounds fundamental, but how many of us don't change them once every six months to a year? I let my 10xK dual compact lamp go past the "grey rings on the ends" point to "just won't come on!!!" The actinic held up a little longer but was ailing. Shame, I know better!!! After the lamps were changed, the fishies ran in the reefs and hid for a quarter hour. This Sunpaq 10K has a nice glow to it. Consequently, coralline algae growth tapered but some of the nuisance algae disappeared. Now I remember why I used to spend so much time watching this tank during the photo ON period. WOW....so much better....check those lamps!