Light up your aquatic life with the Zoo Med 420nm Actinic Coral Sun T5-HO Fluorescent Aquarium Bulb. This high-output bulb promotes the growth of essential zooxanthellae algae that’s vital to photosynthetic corals and invertebrates. It’s designed to distribute light evenly across your tank water’s surface and emits less heat than a metal halide lamp. Each bulb offers up to 10，000 hours of stunning illumination and is great for use in saltwater aquariums. Combine with a Zoo Med Ocean Sun HO-T5 lamp for a "deepwater" tank effect or with a Zoo Med Ultra Sun HO-T5 lamp for optimum viewing of your fish and corals (each sold separately).