When changing lights, you need to be ultra aware of changes in intensity (par) and spectrum. Ideally, you'd want to try to match both of those to what you were running before, and make changes slowly from there. Even then, changing from T5 to LED or Metal Halide to LED can be a shock to corals even when doing your best to match previous lighting. While a par meter would probably give you a good idea on par levels, matching spectrum is going to be somewhat of a guess at best (unless you have some high dollar equipment and knew your previous lighting spectral graph). However, we can probably make some educated guesses / suggestions for each color channel for your radions based on what you were running before if you share that information as
@BoomCorals suggested (i.e. T5, # of bulbs and each type, Metal Halide, wattage and bulbs, or other LED- fixture and settings used on it). Just guessing from what you posted earlier, my inclination is that your white channels are too high (and perhaps the red and green channels are slightly high as well, but concern me less than the white channel settings). The radion SPS AB+ program evolved / created to mimic a known / proven T5 bulb combination and it runs the blue, violet, and UV channels at 100%, but the white, green, and red LED channels are only at 24%. In the interim, I'd recommend reducing your intensity and / or photo period to reduce stress on your corals. Of course, you will want to monitor tank parameters. While we like to focus on lighting, it's very possible that you may have other issues and this lighting change is just the final stress component that started the decline. It can be very frustrating. I know I have certain SPS corals that if I look at them wrong, I swear they can sense it and will start to die just to spite me.
