i have a community tropical fish tank that has been running for about 6 months now and "dirt" has seemed to collect on my plants...at first i thought it was hair algae then i treated the water accordingly but had no effect on this muck, or what i thought was hair algae catching the dirt.
Hi, it sounds like brown algae, quite common in new set ups. It should reduce or disappear as time goes by. You could help by reducing lighting times and not over feeding. You should just be able to rub most of it off your plant leaves.