I have a concerning question about my SPS corals in my 150 gallon reef ecosystem. I have many types of SPS corals and find that some of them will bleach out over a very short period of time. They may be healthy for weeks, months, and sometimes only days, and then will begin to go white and then eventually become entirely white. My chemistry is right where it should be:
pH = 8.3
dKH = 10 to 12
Calcium = 400 to 450ppm
Nitrates = 0 to 5 ppm
No ammonia or nitrites
No phosphates
I dose with kalkwasser, and also use Liquid Reactor. I dose also potassium, and put in 4 drops every other day of Lugol's iodide. I also put in about 3 capfuls of Purple Up every other day.
Any suggestions as to why these stonies bleach out. I have a salinity of 1.025 and I have lots of current flow in the aquarium. I use a 72" Aqualight with (3) 150 watt each 20K Metal halides and (4) 96 Watt actinics. Everything is thriving well, but those occassional SPS acropora digitata.