Brown algae question
hi guys, it's been a while. back in early january, i started a little 3-gallon tank for my betta, & generally it's been doing ok. it's lit by an led fixture plus natural light, & i put a couple plants in it to start, just some java moss on a piece of driftwood, an anubias nana , some marimos and a little banana plant (predictably didn't make it with such low light but I had to try! they look so cool.) for the first couple weeks i had some pretty bad brown algae, but I read that this is normal for new tanks and sure enough it cleared up after a few weeks, and any algae I get on the tank walls & hardscape is green now & much less persistent.
however... while the anubias has been thriving, and sending up new leaves all the time, it keeps getting its leaves covered in some kind of slick, dark brown-black algae growth. it's driving me crazy, because it doesn't seem to ever grow on anything else, just the anubias. every week i rub most of it off the leaves gently & most of it comes off but I can't remove all of it, there are too many bumps and crevasses isn the leaves and it really sticks there. the plant is doing well, but i'm afraid if i left it alone the algae would block all the light it gets pretty quickly. no to mention it looks super grody. is there something I can do to get rid of this? it only grows on the one plant as far as i can tell, so if i get it all off somehow will it stop coming back- and is there any way to clean the leaves more thoroughly than rubbing them by hand without damaging them? i have some amazon frogbit coming in the mail this week, will adding more plants help or hurt this kind of algae?
my substrate is sand, the tank is filtered & i put in 2 drops flourish once a week if that helps.