I culture daphnia in both indoor (basement) and outdoor bins. I could never produce enough green water to sustain even a small number of daphnia. Instead, I feed spirulina and pea powder mixed with water and refrigerated between feedings. Some also feed proofed yeast. Also, the outdoor bins get fallen leaves and grass clippings as the bacteria from decomposing organics is also a food source. (In nature clouds of daphnia are often found in ponds with decaying leaves). In my outdoor bins, I use a box like filter filled with bio-media and a slow flow of air for oxygen and to encourage beneficial biology to prevent an ammonia spike as often daphnia cultures crash from over feeding resulting in deadly ammonia. Partial water changes are also important as daphnia is very sensitive to water quality. They are often used to test water quality (like a canary in a mine). The outdoor bins are also a great place to collect mosquito larvae which is an excellent tropical fish food.
I also culture a warm temperature strain (55° - 75°F) of white worms that I highly recommend. They are very prolific and very nutritious - the fish go nuts for them. I culture in shoebox size containers in my basement on the floor under a workbench. (Some strains require much cooler temps and are often cultured in wine coolers).
David Ramsey has a good primer on culturing white worms.
You might also check out this collection of
Youtube live food cultures.