nah, from what i understand the brown algae aka "diatoms" isnt harmful at all, just a nuisance. Its appearance isnt a bad thing though. It means that your tank is nearing the back end of its cycle and soon your tank and water levels will start to stabilize.
Try doing a forum search on "brown algae" or "diatoms". There are tons of these on the boards that will further help you with this problem since it is very common.
In my 55 i am just finishing up my brown algae stage, i hope. My snails, are absolutely pigging out on the stuff. I suggest a clean up crew for your tank as well. Imo, the crabs and snails play a very important role in the overall scheme of things and without them you could be setting yourself up to have very unstable water conditions down the road. Imagine if the garbage truck NEVER came to your house, thats about what it would be like for your tank if you didnt have a cleanup crew of some kind.
I am newbie too and by NO MEANS and expert, just trying to help.
