Join Date: Feb 2012
Location: Washington, USA
I would agree with your assumption. Many new tanks get brown algae (diatoms). I had it myself, but I cured it last week.
I don't know if the lighting is the problem, because I read that lighting has no affect on brown algae prevention.
To be sure, I did several black outs. I don't know if it did anything.
I think your algae is thriving on the fertilizers that were put in. That was the case in my own tank.
There wasn't enough plant mass to take up the excess nutrients. I cleaned out as much as I could, did a big water change, and added plants.
I threw in some root plants and let them float. I also added water letuce. I'm now noticing a great growth in the floating plants. Good luck to you!