Advice? What are these?

I have these brown or dark purple dots on all my rocks. The rocks are caribsea life rock so they came purple. Does anyone know what these are? (last photo of all)




Thanks.

 

Can't see the photo, but sounds like the formation of coraline algae.

 

I wondered that at first but there are too many of them and separate from each other.

 

Can you upload a new photo? My web page says its a bad file.

 

Can you see it if you click on 'last photo of all' on the original post?

 

Looks like coralline to me. It spreads pretty quickly into small spots. Here’s mine from years ago on white rock

 

I'm hoping so.

 

Can you upload a photo of the rocks with the lights on full white? That will really help

 

Here is another link,

Rocks

 

Here is a link to 8x zoomed with white light,

Rocks

 

Q

Quite a bit going on there. It looks like you have either hair algae or Cyanobacteria. That would be the dark brown patches. The lighter patches seem to be either coralline or maybe bubbles on the algae. You definitely have some coralline in there. Do you have any turbo snails?

 

I took a rock out when I did a water change tonight and tried to scrape some off. It didn't come off easily so neither filamentous hair algae nor cyanobacteria. Maybe it it is coralline? Like a deep red one?

Oh, someone in another forum asked me to post nitrates and phosphate levels. They are .2 and .02 respectively.