Montipora Encrusting sps

[BigLarry]

I have a green montipora frag. It has slowly been encrusting the rock its on and has a small stem sticking out in the middle. Recently over the past 2 1/2 weeks a redish brown growth started on it. It has covered most of the stem.
I would like to know what it is and how to cure it. The frag is about 5 months old and has been doing well until this growth started.

 

[Deanos]

If the reddish brown growth can be blown off easily, it sounds like cyanobacteria.

 

[jackson6745]

Larry what are the water parameters and flow in your tank?

 

[ctxmonitor]

a pic tell a million words. you say a new redish brown growth from the coral or its covering the coral?

 

[BigLarry]

It sounds and looks like cynobacteria. How do I get rid of it?

All of my other corals are softies or LPS hard corals. They are doing well. The Montipora frag is the only sps I have. Tank size is 55 gallon with wet dry made into refegium rated to 100 gallon and 10 gal sump which houses a Euro Reef skimmer and return pump (796gph).
Water flow - 1 275gph ZooMed wave maker on left side. Provides strong current onto SPS.
1 175 gph ZooMed wave maker on right side.
PH=8.2
Calcium=380-400 (depends on time of day. Dose daily with Liquid Reactor- 6ml and 5ml Reef Calcium)
Nitrate=20
Ammonia=0
Nitrites=0
Akalinity=220
Phosphate= 0- .05