• Change your lamps on a regular schedule; use a light meter to ascertain when they have lost more than 25 percent or more of their output.
• Purchase or borrow a PAR meter to use in measuring lamp life and for checking light levels in your tank.
• Start your new corals off lower in the tank so as not to light shock them if they have been kept in lower-light levels than your tank.
• Keep a record of lamp changes, lamp-type changes and the appearance of your animals. This will help you track changes that tend to be gradual.
• Keep your fixtures and glass shields clean and free of salt and dust.
• Avoid moving corals, clams or anemones from low-light zones to high-light zones quickly.
• Don’t replace all your lights at once but do so in stages; it’s best to be able to either raise the fixture or decrease the photoperiod when breaking in new lamps to avoid light shocking your corals.
• Avoid removing the glass cover from your fixture. This cover protects the hot lamp from splashed water, and you and the aquarium from shattered lamps and the chemicals they contain.
• Never combine metal halide and fluorescent lamps in the same fixture, as they are designed to operate at different temperatures.
• Avoid making changes in lighting just for the sake of making changes.