Brown film on aquarium walls: good or bad?

[theflyingbernard]

I've had my 10 gallon freshwater aquarium for a few months. It's developed a brown film on the walls of the aquarium. It's enough to look dingy, but not enough to obscure my view of the aquarium.

Is this good or bad? Should I clean the tank? If so, how?

I test for ammonia/pH/nitrates/nitrites, but want to know if I'm missing something by letting the tank get dirty.

 

[Mebbid]

It's most likely just increased growth of diatom algae. It should run its course before too long. It isn't necessarily harmful but can look ugly, I find nerites do good work at removing it as well as just cleaning the glass.

 

[Fishperson]

Yup, its brown algae AKA diatoms, it is completely harmless, so you can just scrape it off or whatnot, or add some snails. Not much is really known about getting rid of it/preventing it.