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Have you tried moving it to a more shaded area? The edges do seem on the light side, might just need more time to acclimate.
My favia didn't like direct light at all. Some didn't grow while the other started bleaching. I put in a more shaded area like under a cliff of a rock toward the bottom and they started gaining color and growing like crazy again
doesn't sound like you have a lot of light in there. Its possible if its a newer tank it doesn't like the chemistry. Do you have a higher alk and lower nutrints? Runnin a gfo or PO binder?
Keep in mind with light, it depends on the amount you have that creates ratios. . If you have 200 to 300+par on the sand, the "shade" can be 50 to 100 + par. So kinda a myth about direct light. but id the lfs has had it in 50 par and you drop it into 150 par, yea it may not like it.
IMO, don't mess with PO, it will go down and stripping too fast will anger a lot of coral. also PO4 is food. too little is worse than too much.The lfs light didn't seem to bright and the lights where placed really high altho they used a kessil light it was at least 3 ft above the tank.
Ph is perfect 8.3-8.4
Po4 was at .25 so I'm running some phosguard to lower it
IMO, don't mess with PO, it will go down and stripping too fast will anger a lot of coral. also PO4 is food. too little is worse than too much.
the 8.3 to 84 is likely due to new rock and sand buffering the water and giving you a higher alk. that will drop naturally to as the outer layers dissolve and are coated by bacterias and algaes. hopefully you've been avoiding PH buffers(pure alk)
What light/s was it in from the previous tank?
Kessil 160 maybe....
Man at the end of the day too little light would do much less harm over a longer period of time than too much. Very easy to shade it and see what happens. Very possible it's a chemistry issue, but my low light corals always suffer from too intense light and not enough flow. And just speaking from my experience on this one, but i've lost far more corals from high PO4 than too low.

