What is this?

[aprilschutt]

Can someone please tell me what this is? There are these hard looking (almost calcium type deposits) small dots all over my live rock and the back walls of my tank. For some reason it has not formed on the front of the glass though but maybe its because I clean the front of the glass every few days? Anyway, is it harmful, normal?

My tank is almost 4 months old but these spots have been starting almost since the beginning of the end of my cycle. Water parameters are...

Ammonia 0
Nitrite 0
Nitrate 5
phosphate .25
Alkalinity 9
Calcium 420
Magnesium 1350

I've attached a picture also. TIA

 

[cloak]

Spirorbid worms most likely. (harmless)

 

[aprilschutt]

Do people usually just scrap them off?

 

[cloak]

Not really.. Were you planning on keeping the back panel clean or just letting Coralline algae run wild?

 

[aprilschutt]

Planing on the back and two sides be coraline. And a do see patches starting to grow!!

 

[cloak]

No worries then.

 

[aprilschutt]

Thank you so much. I've been amazed at all the knowledge on this site. Super helpful to a newbie like me.

 

[Mcgeezer]

I've got a very established system and have thousands on my back glass. They are harmless.

 

[mixed93cube]

+1 they are harmless

 

[jangy]

Do they spread? Any particular water conditions they like? I only have about 10 of them (been that way for a month), so just curious.