Loosing Purple

[djk1]

I have a 150 gallon tank running for about a year now and something weird has happened in the last week or two. Everything was purple on the back walls, the rocks, and coral stocks. I have noticed I am slowly loosing the purple algae. All levels are good, I tested a few days ago including calcium. Any reasons why?

 

[Andrew]

Did you change your lighting? Whats your current calcium reading?

 

[djk1]

No lighting change and the calcium is at 400 ppm