Corals losing skin? Red turf algae?please help!!

[motoman37]

I’m having a few issues, first I have been watching this red turf algae spread.
Second issue is most of my corals are losing their skin.
Parameters:
Alk 8.6
Cal 450
Mag 1480
No. 0
Po.0
Equipment:
150 gallon
40 gal sump
D9 bubble magnus skimmer
2-mp40
Geo cal reactor
Brs dosing pump for cal
Dual brs reactors carbon/gfo

I’m doing weekly water changes.

 

[RobZilla04]

Look toward lack of nutrients, specifically Nitrate & Phosphate. If you have a low or ultra low nutrient system drop the light intensity and Alk. What test kits are you using? A good option is to send a water sample for full analysis, but that takes a little time. You may have no coral left by then. Most time STN or RTN is hard to diagnose and much harder to correct.

How old is the system total? The lack of coralline algae signals the tank may not be ready for SPS coral yet.