Darn lando, you beat me. Trace elements are no where near the same thing as plankton. Traces are like vitamins....plankton is actual food.
Typically only the large reefs with tons of corals require trace supplementation...water changes take care of traces in smaller systems.
Before adding an anemone, the tank needs to be stable for at least 6 months. Since it takes a few months for a tank to truely stabilize, you're looking at 9-12 months for a typical time frame before you want to add an anemone. You must also make sure you have sufficient lighting. Even a BTA should be given 2-3wpg, so it can produce it's own energy from teh light, requiring less hand feedings from you.
Also I think anemone's eat food larger than microscopic plankton. I see photos of clown fish feedign bits of mysis shrimp and krill to anemones.