High Nitrates After Cycling Complete

I apologize if there's already a topic that will answer my question, if so please point me in that direction.

My girlfriend owns a 10 gallon tank. It went through it's cycle and has been balanced out for about 2 months now. About a week and a half ago, the nitrates are in the 120 ppm range. We haven't added any fish and are doing the standard water changes. I was wondering what would be the best course of action to lower the nitrate levels. Algae seems to be building up a little bit. There's some green algae on the one side of the tank, on the plants and decorations, and on the filter's intake tube. It's not heavy, just little dots of algae. We did a 40% water change the one night with absolutely no affect. I bought some EasyBalance water treatment that has Nitraban in it. We put the first dose in about a week ago, still with no effect. Should we just up the water changes? Scrape the algae off? We have Chinese Algae Eaters, well that's what we think they are anyways, and I've been reading a few things that said they don't even actually eat algae. As always any help is appreciated.

The tank uses an above gravel power filter. We do a gravel vac with each water change. We have five Raspborahs (sp?), 4 neon tetras, a platy, 3 red eye tetras and two chinese algae eaters. I think it's a bit OS, but that'll be fixed soon.

Nitrate level when we checked tonight was closer to 80 ppm.
Nitrite was right around 0
Hardness was about 80
Alkalinity was 80
pH was about 7.2

I need to get a new Ammonia test kit, so I couldn't get a reading on that. From previous experience I know not to put the tank near any windows or any places where the tank might be getting exposed to a draft or air from a heater vent.