Are diatom and brown algae the same thing?

[plecc83]

Hi all.
To my limited knowledge, diatoms are a microscopic organism encased in a silica shell. That thrive in a high silicate/phosphate environment. Please correct me if I'm wrong!
Is this what others are referring to when they use the term "Brown Algae" or is brown algae a completely different issue?

I am curious because I'm having a persistent ongoing issue with brown stuff developing all over my anubias and wood, the brown stuff has a red/brown tone to it very similar to the colour of the rosewood but a little brighter, it only appears in the better lit areas. Sometimes as a thin dusty like coating and others as blotches over the leaves. It can be removed fairly easily with your thumb or a toothbrush.
the tank also has a bit of black beard algae around the edge of some of the older leaves.

Aquarium = 120L (4Ft) with Fluval 305 canister
Substrate = Pool filter sand (supposedly 95% silica)
Hardscape = Loads or Rosewood (the rosewood is many years old, it no longer leaches any tannins. It could be contributing to high phosphate)
Plants = Various Anubias only
Lighting = Very low for 8 hours a day
Stocking = Very low 2x zebra loach, 8x Sterbai Corydoras
Schedule = Weekly 25% water changes, filter cleaned every 2 weeks

I don't currently have a test kit for silicates or phosphate, but happy to pick one up if required. Can someone advise the most logical way to try and track down the source of this problem? Thanks.

 

[Naughts]

Maybe brown algae could be an inaccurate term for diatoms but I am unsure in what context you heard it? If you post a photo of your “algae” someone will identify it. Your description of red-brown stuff that can be rubbed off could well be Cyanobacteria.