browning

[goochesfish]

What causes SPS to turn brown? It only happened to by blue corals. All the green ones and monty's are fine.

 

[tate1]

I had the same issue on 2 frags. They improved when I changed their placement in the tank.

 

[sedor]

If the browning were occurring on everything, the common answer would be a nutrient issue causing the zooxanthelae to overproduce, causing the coral to appear brown. It could be that your blue corals happen to be more sensitive varieties and are reacting to something sooner than the others. Monty's for example tend to be more resilient and will "put up" with a lot more before showing signs of stress. I would test for NO3 and PO4 and move on from there.