What Is Moderate Saltwater Lighting?

The appropriate level of lighting for a saltwater aquarium depends on the animals one decides to keep. There are different requirements for fish only, fish only with live rock, or a reef aquarium. While the standard measure used to be watts per gallon, with new advances in aquarium lighting this can only be used as a rough guide.

  1. Moderate Lighting

    • Moderate lighting for a saltwater aquarium is intense enough to keep the various photosynthetic organisms that live there happy. If the aquarium has too little lighting, these animals will not survive, yet if the lighting is too intense, it can actually be harmful to your aquarium's inhabitants. Since corals and other marine life are photosynthetic, moderate lighting helps them strive and grow.

      German T5 fluorescent is the new staple for the saltwater aquarium and has become synonymous with what constitutes "moderate" for the saltwater aquarium. Always keep in mind that "moderate" is a subjective term for lighting a saltwater aquarium. Lighting is wholly dependent on your animals' unique needs.

    Fish Only and Fish Only With Live Rock

    • If the goal is to keep colorful saltwater fish, then the only concern is being able to provide enough light to view the inhabitants. One watt per gallon of fluorescent lighting is more than sufficient.

      Live rock requires light to thrive. Moderate lighting for this type of tank would be around two watts per gallon of fluorescent lighting.

    Soft Coral Tank

    • A soft coral reef tank requires slightly more lighting than a tank with only fish and live rock. While most soft corals are photosynthetic, they are the least demanding, with regards to light, of all corals. You should aim for two to three watts per gallon of fluorescent lighting. T5, compact fluorescent and VHO are all good choices.

    Large Polyp Stony Coral Tank

    • When it comes to lighting, the large polyp stony corals are more demanding than soft corals. Three to four watts per gallon is a better range for these corals. VHO, metal halides and high output T5 are all acceptable lighting options.

    Mixed Coral Reef

    • For the most part, a mixed coral tank falls into the arena of the large polyp stony coral system. Three to four watts per gallon is a good range, and the lighting choices can be found above.

    Small Polyp Stony Coral Tank

    • A small polyp stony coral tank requires oodles of light. These corals are the most light-hungry of all corals. Four to five watts per gallon is a good starting point for these. While any lighting can be used for supplementation, your main lighting should consist of metal halide or HO T5 only. Most other lighting can't support these animals.

      Other invertebrates, such as giant clams and many anemones, are very light-hungry creatures. Not only do they often rival small polyp stony corals in their light requirements, but they derive much, if not all, of their food from light.

      Keep in mind that this is only a guide. There are many factors that contribute to what is considered moderate lighting for a saltwater tank. Reflectors and tank height can also affect the number of bulbs used.