Changing the aquarium bulbs is not a simple matter

One of the most common questions regarding aquariums, whether it’s just with fish or with fish and plants, is when to replace the bulbs. Although fluorescent tubes can last for several years before burning out, experts and manufacturers recommend replacing the lamps up to twice a year. Is this the right way to go, or are the light bulb manufacturers just for the money?

Although you and I may not be able to tell the difference in the quality of light, the amount of light that an aquarium light emits will decrease over time. With both saltwater tanks and freshwater tanks with plants, many experts recommend replacing the bulbs at least once a year.

Of course, the true answer is never that easy. If your tank only contains fish, you may be able to use a light bulb until it burns out or if the algae starts to build up. Without plants in the aquarium, nothing depends on light for the photosynthesis process. Keep the bulb for as long as you like, or replace it when you want more light or better quality. If you can no longer see your fish, it may be the perfect time to replace the light.

With a plant or a reef aquarium, the situation becomes more complex. You will need to replace the bulbs every six to twelve months for standard fluorescent lights, and every year for up to 18 months for very high output aquarium bulbs. Even with VHO bulbs, you may want to replace them sooner rather than later, to maintain the quality of light necessary for plants to thrive.

The main reason to replace the bulbs is to maintain the proper amount of light needed for the plants to grow and to prevent algae build-up. Some aquarium lighting experts even recommend changing bulbs every six months, as the fluorescent bulbs used will diminish over time.

Fortunately, your fish’s health won’t suffer if you wait too long to change bulbs. The main problem with older aquarium bulbs is that not enough light is emitted to keep the plants growing and alive. This is noticeable through a phenomenon called “dimming,” where the neon colors of corals or clams fade to a brownish hue over time as the quality of the light they receive degrades.

Very high-output bulbs will last longer, but are more expensive than standard fluorescent lamps. VHOs also use more energy and produce more heat than standard bulbs. Some very high output bulbs also have special end caps and require a different ballast than the standard variety.

Changing the bulbs in an aquarium is not as simple as waiting for them to burn out and then replacing them. You need to be much more diligent about the quality of light your fish and plants get, and plan to replace the bulbs based on that. Most aquarium bulb manufacturers specify the nominal lifespan of their bulbs, as well as how often they need to be changed to maintain light output.