It is this fact that has made coral taxonomy historically difficult and has posed numerous problems for aquarists. The choice of lighting to use contains numerous variables that must be taken into consideration. The first of these is the type of invertebrates you wish to keep. Another variable is the natural habitat that the coral was collected from. Therefore, additional blue light will only have beneficial results and should be favoured over the addition of higher intensity lights that have more red or green light.
Wattage is important too.
Obviously one must take into consideration the type of invertebrates one wishes to keep, at what depth they normally occur and the size of the tank before selecting the wattage of bulb to acquire. Some European aquarists recommend that one 250 W HQI lamp, at a height of 35 in. What has failed to be taken into consideration are the following facts. First of all not all our aquarium specimens come from such shallow areas and have no need of such high intensities. Secondly, even in these shallows, the light intensity is far from constant.