The Arcadia Marine Blue Actinic promotes welfare of invertebrates. For a marine aquarium to realistically represent reef life, it is essential to provide the best conditions for corals and invertebrates to thrive. Most important in this is the survival of zooxanthellae, a specific form of algae, which symbiotically assists the invertebrates to feed and remove waste matter. In nature, the sun provides over 100,000 lux (lumen per sq. metre). At depths of typically 5 to 10 metres, where many of the corals and invertebrates are found, the visible light to be seen is basically only in the blue wavebands, thus the familiar blue appearance. All the other wavelengths, particularly reds have been absorbed and filtered out by the salt water. This remaining blue light is the light which invertebrates have evolved to utilise for zooxanthellae symbiosis.