What if this stuff?

[Andrew Schubert]

My tank had been up 5 months. About a month or so ago this algae stuff has been growing on my glass, especially the bottoms, edges and behind my gyres. Some I can scrape off, but man a lot of it it doesn't matter how much I scrape it just won't come off. I have an acrylic tank, so I have an acrylic safe scrubber with a plastic blade.

 

[Coralreefer1]

Diatoms!

 

[Andrew Schubert]

Diatoms!

That's weird bc I had it when I first set the tank up. It was on my sand bed and rocks. But after I installed a uv sterilizer about 2 months ago it all went away. Yet never showed in the glass till After it goes away on the sand and rocks. Is that normal? Lol

 

[Coralreefer1]

I don’t know too much about them other than they are unicellular and surrounded by a cell wall made of silica. Most are photosynthetic, though a few can live in the absence of light if provided with an organic carbon source. They range in length from 2-200 micrometers. They double in size roughly every 24 hours and their life span is about 6 days. They are a type of phytoplankton.
That is definitely weird how they only show up on your glass after they disappear from your sand and live rock.