Maxspect Razor 120

I have 2 Razor 120's over a 75 gallon (long) tank. I have the lights on the stands, mounted to the tank. I was running the lights at 70-80%.
I purchased a birdsnest coral, and when I bought it home, within a week it started bleaching... and I've turned down the lights to 60%, but they don't seem to be recovering. Is it possible these lights are too strong at a setting of 70-80%? Perhaps even 60%?
I know many of the reef-ready tanks are 24" high. The 75 gallon is about 6 inches shorter. Do you know what the par readings are for the 120 at about 18 inches?
I've read many reviews online of the Maxspect 120... many folks say they are too intense at full brightness, and other says they aren't bright enough. A bit confusing.

FYI, I know bleaching can be caused by many things. But tank parameters Ca, Alk, Mg, NO3, PO4 are all within range and I perform 20% water changes every 2 weeks.
I believe its the lighting.

Thanks for your help!