A colony of white spots just appeared on live rock

[jeffaquarius]

I have no clue what these white spots are which appeared about 2 days ago. I started using the Reef Crystals salt by Instant Ocean about a week ago. Before that was just the Sea Salt. My dKH was too high a week before with low carbonate of 360 so I replaced 25% water and added B-Ionic Calcium Buffer 1 & 2. Other parameters are PH=8.2 Nitrate=15 Phospate=0 Sp.G=1.025 Temp=78.

 

[ktomminello]

Looks like calc worms

 

[jefferzbooboo]

They're a type of worm that looks like a feather duster, eventually you'll catch one that has its "feathers" out, they're red if I remember right. They're completely harmless, I've had them in my tank for 4+ years and they come and go.

 

[fort384]

Appear to be spirorbid worms to me. As jeffer stated, harmless, and they come and go. More info here:

Xtalreef - Reef Saltwater Aquarium

 

[jeffaquarius]

If they are all true then I am excited to have more unexpected creatures in my tank. It's just surprising they suddenly sprouted so many in same spot. Few are spread out singly on other rocks.