The ideal placement of the coral or invertebrate within the aquarium is the culmination of its lighting and water flow requirements, as well as their temperament. By placing the corals and invertebrates properly within the aquarium, you will create in time a beautiful harmonious display of a wide variety of species.
The bottom of the aquarium is the ideal place for many of the "Aggressive" corals and invertebrates that require "Moderate" Light and "Low" Water Flow. These are typically LPS hard corals, anemones and non-photosynthetic invertebrates. When designing your reef display, be sure to leave plenty of open sand at the bottom of the aquarium for future additions of these species.
The lighting system on the aquarium will ultimately determine both the species suitable for the aquarium, as well as their placement within the aquarium. Species with "Moderate" Light requirements may be housed in a system with lighting that falls into the "Low" category, as long as these species are located at the top of the aquarium. The same holds true for incorporating low light loving species into a brightly lit aquarium. These species will simply need to be placed lower in the aquarium.
Monitor the health of all species in their new location and allow time before determining if a different position within the aquarium is necessary. Photosynthetic organisms alter the amount of zooxanthellae cells within their structures to compensate for different intensities of lighting. It is important not to move these organisms too frequently, as it will place undue stress upon them in the short term.