Recommended Lighting for a Saltwater Aquarium

Saltwater aquariums are demanding when it comes to lighting needs. Many corals and certain species of fish need adequate lighting to thrive. Lighting needs are based on watts per gallon, so large tanks have increased lighting requirements. There are a variety of lights available, but the right one depends on the variety of life and decor you intend to keep in your aquarium.

  1. Types

    • Fluorescent bulbs come in three stengths: NO (normal output), HO (high output), and VHO (very high output). VHO bulbs require expensive light fixtures called ballasts, cost more to run, and produce more heat than NO bulbs. If you are going to keep soft corals in your reef, VHO bulbs might be necessary.

      Compact fluorescent bulbs are similar to VHO bulbs but produce more wattage from a smaller bulb. The bulbs get very hot with temperatures that exceed that of VHO bulbs. You will need to purchase a fixture with a built fan circulator to keep the bulbs from getting too hot. Another option are metal halide bulbs typically used for reptile setups. These come in many colors and are easy on the power bill in comparison to fluorescent lights.

    Wattage

    • An acceptable number of wattage for a saltwater tank is 3 to 8 watts per gallon depending on what you plan to house in it. Fish only tanks have less lighting requirements and need the minimum of watts per gallon. VHO fluorescent bulbs are ideal to achieve higher wattages of about 5 to 8 per gallon. Metal halides are the best choice if the tank has certain types of soft corals such as acropora, pavona, goniopora species. Metal halides focus heat just on the area beneath it. They are just a metal fixture surrounding a bulb, so they can pose a serious burn risk.

    Scheduled Lighting

    • Marine tanks with a full compliment of fish, live rock and coral should be lit about 12 to 16 hours a day. Aquarium lighting is less critical if you choose to have a fish-only tank. Those tanks should be lit about 10 hours a day.

    Caution

    • Avoid using VHO bulbs in NO light fixtures. It may be tempting in order to save money, but could cause a fire or blow out since the light fixtures themselves are not made to handle such high output. VHO lights should be used with extra cautionor not at all in acrylic tanks. Those tanks are more vulnerable to heat damage from the VHO lights.

    Maintenance

    • Change your lights when you notice your bulbs are not as bright as they were originally. Most reef keepers change their bulbs around two times a year. Always have spare bulbs on hand so burned-out bulbs can be promptly replaced. Tanks with fish only will generally do fine if you have NO fluorescent bulbs. But tanks with corals, anemones and live rock too will need high wattage lighting like VHO lighting or metal halide lights to keep everything in good health.