Right now with two t5s ATI, coral plus and blue plus, I'm running them four hours a day and running the Radions at 50% max for 7 hours a day with 100% for UV, RB and Blue, 24% for white, green and red. I just turned down the Radions from the high 50s because of some bleaching of corals high on the rocks in the center of the tank. My new t5 retrofit will arrive tomorrow with another blue plus and coral plus. I have a par meter so my goal will be be to reduce the par somewhat in the middle/top of my tank and keep the par in other areas about the same. I'm guessing that, in order to do this I'll need to turn the radions down to 25-30% of max.
The guys at ABC were kind enough to let me play with my par meter in some of their tanks, including the main 180 tank. Their par toward the top of that tank was about 150 max before correction for the dispersion effect of the meter. After correction, you're looking at about 200 par, much lower than the par at the top of my tank, particularly under the center radion.
Matt