Do we have any Algae or Aquatic plant life specialists here?

I'm in need of someone who is familiar with algae and identification / recognition of a certain type of plant life.

I have a sample with what I believe to be a brown algae in it and would like to confirm or refute this suspicion with someone more qualified than I am on aquatic life.

Bonus Round: Microbiologists too as a biofilm has appeared on the top layer of the algal bloom.

Edit: Okay I am told that this cannot be an algae as it would have more polyps and be more green so I'm thinking it could be a filamentous bacteria or a water mould or fungus. Any input would be great.