Most coral benefit indirectly from Phyto... only a few benefit directly. Phyto feeds bugs. Bugs reproduce & feed coral. This doesn't often happen in a 10 gallon tank.
You'd be better suited to use live phytoplankton such as DT's. Kent's phytoplex is a good product, but whatever is not eaten will foul your water. Live phytoplankton will survive in your aquarium and will actually feed on the nutrient in your water and help to purify to a small degree. Every little bit helps, especially in a Nano
Myk.