I did change my T-5's with halides. After using the halides for about 5 weeks I went back to the T5's. I did it because my corals and anenome didn't seem to like the halides. Under the T5's the color was better and the polyps openned longer. The shimmer on the halides was nice but to me after a while it became annoying, to much shimmer. It's kind of like our swimming pool. We have a pebble sheen surface which replaced the old plaster. It was expensive but the pebbles include different colors and also abalone shell and crushed mother of pearl. In the sunlight we get a high shimmer like the ocean when we are swimming. When the water is calm we get better color. I think that's why we see better color in the tank because the shimmer is toned way down. JMO