There aren't any hard and fast rules. If you are using something bottled like Marine Snow, MicroVert, various phytoplanktons etc., follow the instructions on the bottle. For the time being use the low end of the the recommended dosing and see how the corals are doing. You don't want to overdo it and risk polluting your tank. Other make their own coral and fish/invertebrate food, you can do a search for these formulas on RC and other places.