Algae on Zoa?

[Leyth]

Hey guys, my Zoas have been in this location for a while and they have tripled in size in months. However, I had a algae break out and while I got it all under control, my Zoas haven't really recovered. In fact, I keep seeing this brown stuff on them every day. It blows right off with a baster, but it comes back the next day. Any ideas?

 

[jasonb87]

Whats your tank parameters?

 

[Leyth]

78 degrees
8.2 ph (depends what time i test)
0 ammonia
0 nitrites
5 nitrates

 

[jasonb87]

Phosphates?

Any change in flow recently?