I feed mine a lot of fish poop, as well as phytofeast and rotifeast. Nutrients in the system helps them with their growth and color. There is always the other side of that as well. Zeo systems are very low nutrient tanks and may zeo people have achieved great color.
Maximum is a term that is described by each individual. If your corals are healty, they will grow. There is no rule of thumb as one coral will always respond differently than another.