Growing out corals.

[DorySaid]

I'm assuming your phosphate is .2 not 2.0
If it were 2.0 then thats your answer to the browning. That would confirm my estimate that your nutrients were too high. But lets assume they were .2 which is not horrible by any stretch.
I dont know what size your tank is so i cant say if 250ml of gfo is too much but you gotta kinda watch that. Extreme quick changes can cause even more trouble.
As far as your leds, i dont think you'd need to turn them down. If you had too much light to what they were used to, they would likely bleach. Try to inspect the corals for any signs of bugs or pests just as a general precaution, but browning is usually nutrients related, not too much light.
By the way, what test kits are you using and are they fresh? ( Not expired )