Brown algea (diatoms?) on pennywort

[roomtobelieve]

I have a 29 gallon tank with a few small fish (guppies, neons, corys) and I want to gradually switch the plastic plants for live ones. I love the look of the first plant I got, which is pennywort. It grows really well and quickly. The new growth looks beautiful and green, but the mid and lower level leaves are getting covered in brown stuff, which I assume is some kind of algea. I also have this on some rocks in the tank and am wondering how to get rid of it and have healthy green leaves again (if I can.. or once they are brown do they just need to be removed?).

The guppies pick at the algea on the rocks, but they aren't doing any real work to get rid of it. I had considered getting a few malaysian trumpet snails because I like their look and I have a sand substrate that they would do well to keep aerated. Will they eat this brown stuff?

Any advice on greening up my pennywort is welcome!
I know that the lighting matters too, we keep it on from about 9am-9pm so we can watch the fish during the day. It's a single bulb - I think it says 22 watts. It's just what came with the tank when it was given to me. So... thanks in advance for any help!

 

[PatrickL]

I had the same along my back glass, and a few of my plants. I have a 45 gallon, and got a rubbernose pleco a while back, mainly because at the time, I REALLY wanted a pleco, but he wasnt eating the green algae, so I held back on his daily algae wafer(he shares it with cories and tiger barbs, and doesnt mind. So I held back on that, and he ate all the brown algae in a day. Thats my experience.