Brown Algae on Plants

I've had my aquarium (10 gallons, Platys and Corys) for a couple of years
now. There is brown algae in my tank that grows on the rocks, the castle
(the kids picked it out), the gravel, and the glass at the gravel line. In
the past, I've occasionally scrubbed it off of the rocks and the castle, and
every week or two I scrub it off the glass at the same time I get the green
spot algae off the glass.

Last week I added some plants (Anubias, Cryptocoryne, and Valisneria). What
should I do about the brown algae that has started to grow on the plants?
It is most noticeable on the broad leaves of the Anubias. I doubt that the
algae is good for the plants---not only is it not attractive, but I would
think it will block light and interfere with photosynthesis.

If it matters, the tank parameters a
pH: 7.4--7.6
Ammonia: 0
Nitrites: 0
Nitrates: 7.5 (somewhere between the 5 and 10 color bars)
-- was higher in the past, but I've brought it down via water changes
and an end to overfeeding
Temperatu 78F

Thanks,
Dave