If u just added them then just give time but if they where nicely colored then browned u have to look at ur nutrient level nitrate and phosphate if truly 0 which unlikely then ur water too clean which happens too guys running biopellets zevoit etc... The other reason sps tend too brown is high phosphate how r u testing this??
Also what is ur flow like??? Low flow might also be culprit.
How long is system set up? Do u have any alage issues?
According to the tests they are zero, the tank has been running since 2008 but I started adding coral probably about 6 months ago, I run phosban in a reactor with carbon, using api test for phosphate. Flow is good I have a Koralia powerhead 1050 plus the return pump from the sump, it's only a 50 gallon tank.no alage problems as of late besides a tiny bit of hair alage, nothing much.
even though salifert is a better test kit its still not reliable for PO4.you would need a hannah meter.im not saying you have PO4.there are many factors in corals browning.is it every SPS you put in or just certain ones.
I had the same issue with my monti cap and when it acclimated to the new light it browned and then slowly the color began to come back.. Could be anything just make sure that it is living and getting growth