I'm currently using one, its about 60-70g.
So far only plants with low light plants (javamoss, javafern, watersprite, anubias nana petite, a bunch of other ferns and unknown plants) THere are also a couple emersed plants as well. I believe emersed plants are supposedly better at nutrient export, but i'm not sure.
Its pretty much nutrient export, the plants us ethe nutrients in the water to grow.