Is this Diatoms

[Cmajor]

Hello everyone. My tank is 6 months old and i have this brown slimy looking alage in the tank with bubbles holding onto it. Its been about a week and a half since i first noticed it. Woke up one morning at it was all over. Did not add or change anything to my regmin or tank. Tank was started with all dry rock and dry sand

125 gallon with 40 gallon sump reef

temp-79.5
Sg-1.025
AM-0
Trates-0
Trites-0
Phosphates-0.04
Calcium-430
Copper-0
Instant ocean salt

Any help on exactly what this is would be helpful. From what i understand is if it is diatoms then i just need to continue weekly water changes and let it run its course. Thanks everyone in advance.

 

[Supa]

I had this happen when I would feed pellets and they would sit on the ground too long, it looks like dynos or something

 

[Supa]

Side note it’s still happening some but I manually remove it in small sections. While cleaning sand bed and or durring WC