Oh sorry, mis guiding you is never my intention..
What ever you do, don't make any rapid changes ..
I assumed you a running somewhere around 6 hours (actual photo period) at high intensity and meant you can dim your lights to see if its working and then if corals still need more light then can increase duration ..
Now that you decreased the Intensity, see If the zoas are actually opening up when all lights are on if they are then slowly drop the light period to 7 hours( not considering the ramp times)
Now that they are comfortable with the intensity and opening up you can keep the photoperiod at 7 hours and slowly increase intensity by 5% every two weeks or so to get. To your desired color/ intensity
Again, don't make any sudden changes. Drop the duration to 7 hrs or so very slowly over a week (some zoa gurus on here even suggest only 5 hrs of photoperiod under intense lighting )
Sorry for the trouble