Promotes growth of zooxanthellae algae; essential for the growth and well-being of all live corals and invertebrates. T5 lights provide more light output than T8s! Actinic 420 promotes the growth of zooxanthellae algae, essential for the growth and well-being of all live corals and invertebrates. Combine with Zoo Med’s Ocean Sun® for a more subdued “deepwater” tank effect. Combine with Zoo Med’s Ultra Sun® for optimum viewing pleasure of live fish and corals. Distributes the light evenly across the water surface. Generates less heat as compared to metal halide lamps. High quality lamp manufactured in Germany.