Algae Issues

use an algea scraper to remove as much as you can. reduce lighting to 10hrs, reduce feeding portions and perhaps skip everyother day. vaccum the gravel and increase water change frequency.

I think that you have diatoms based on the description. It is probably caused by an excess of silicates (From your tapwater or gravel). I would not worry too much about it as it will eventually go away by itself as your tank matures. If the tank is mature, your water source might be high in silicates which would cause this problem to persist. I would then get a phosphate/silicate absorbtion resin to deal with this problem. Otherwise just keep up with your waterchange schedule vacuuming the substrate and scrape it off until one day it vanishes. When my tank was newer I had the same problem but my pond snails and rainbow shark took care of the problem relatively quickly.

EDIT: A reduction in light will actually stimulate the growth of this type of brown algae. Unless you have a problem with green algae, leave your lights on for 12 hours a day.

Diatoms are a form of brown algae that forms almost a fuzzy carpet over everything. Usually starting as small brown spots on a dark surface. Hair algae normally only grows on your plant leaves.

if you have the ability to put up a pic, please do so.. if not, you might try some Google Image searches to find something that looks right.

diatoms come in thousands of forms. some are spots, some colonize in threads... how long has the tank been set up? diatomacious colonies are usually only strongly present in newer tanks, and in those of hard water, IME.

usually the standard green algaes outcompete it in time.

you could have a lighter (in color) form of black beard algae. there are multicellular green algaes that are more brown in appearance (kelp comes to mind).

hence the need for a pic to get much further.



edit: to get some of the more 'exotic' algaes i would suspect you have a phosphorus source... from the tap or somewhere. light, phosphorus and nitrogen compounds are usually the limiting growth factors.