Grim,
I have been using T5s for over a year now, in an 8 bulb TEK light. I am very pleased with the performance and growth I get, but, I have one glaring problem with T5s. Any EMERALD green coral that I bring into my tank either fades or goes to greenish brown. I FINALLY found an awesome deep emerald green monti cap with purple growth rim, as a captive raised frag from my LFS display tank, only to have it start shifting towards an olive drab coloration, just like all the other deep green corals I started out with. Everything else responds favorably to the lighting. I use the following combination (don't know the order): 1 GE 6500K, 1 ATI Aquablue Special, two UVL super actinics, four ATI BluePlus. I like the color that the tank takes on from this combo -- slight tinge of blue, but not too much. The SPS grow like mad, even down on the sandbed, and hold their colors, as do the clams. I have a 4 foot fixture (54 watt bulbs). The corals were either from VHO lit tanks (and look the same in my tank initially for the first few weeks), or from 10-14K halide/VHO combination lit tanks. All of my water parameters are excellent, no phosphates detectable with a D&D Merck phosphate kit AND via a friend's high end Milwaukee "Martini" colorimetric phophate tester, 0 nitrates, 410 Ca, 10dKH, so, my thoughts are it has to be the lighting. Can you recommend any changes in the lineup that may make these deep greens hold their colors and "pop" again?