help identify brown / red slime algae - photo and microscope images

[saltyfish24]

I have a mix of this red algae on the sand and brown slime algae covering rocks/pump nozzle and growing on macro.

Here's a video of the sand's red sheets of algae. I thought it was cyano, but it didn't go away with chemiclean. I took a microscope image and video of brown slime algae and the red-ish sand algae, maybe that'll help with ID?

The microscope video shows a matted mess of brown segmented threads, interspersed with clumps of red colonies of cells and some green colonies.

 

[Subsea]

While I can’t help with identification, I can ask you about your sandbed maintenance because you need to vacume out the nuisance algae from sandbed.

 

[saltyfish24]

While I can’t help with identification, I can ask you about your sandbed maintenance because you need to vacume out the nuisance algae from sandbed.

haha, so true. I've been vacuuming it out every week for a few weeks now. I have a 30 gallon, and I've been taking out 5 gallons a week. The cyano-looking algae on the sand bed comes off in mats really easily when I vacuum it up. I lose a bit of sand every time I do that because the top layer sand comes up with the algae.

 

[EnterName]

Your microscopy recordings show cyanobacteria which matches the dark purple slime on your substrate.

https://www.reef2reef.com/threads/microscopy-thread.1138845/post-14401969 (Post #52, page 3, 12th post on page 3 if you are using the app)

The second image shows some encrusting red algae which is harmless and not the issue (probably coralline algae). The "spirals" are the problem.

(compare https://www.reef2reef.com/threads/microscopy-thread.1138845/post-14401969)

(compare last video in post https://www.reef2reef.com/threads/microscopy-thread.1138845/post-14453182)​