LED's are known to cause bleaching of corals, especially when turned up super bright (like we all want to do from the get go). Unfortunately that's a big change in PAR, and just like every other parameter in your tank, you should strive to keep it stable in the usable range for your corals. You can certainly try to turn it up slowly. Use a window screen with some nylon window mesh in there, cover the tank, and use as many layers as it takes to decrease the intensity of the light for now to what you think it may have been before. Or if you can wire that pot in there to adjust dimming (not as easy as it sounds), then go that route. If it will take you some time to do that, the window screens are an easy cheap alternative. At least that's what I would do!