Algae growth is helpful to a coral reef, but only to a certain extent. It can provide a food source for other coral fish, but too much of it can harm the tank and possibly kill off much of your live coral. In simple terms, it is important to control the light, temperature, and cleanliness of the water in the coral reef tank to ensure that all of the creatures survive. The higher the temperature of the water and the dirtier the water, the more likely the algae is to take over the tank and begin harming the rest of the creatures in the tank. The more advanced you get in caring for your coral reef, the more you will be able to begin mimicking the sunlight that most coral reef environments live well in.
While light bulbs are brighter when they are first used, this is not a good thing for the well being of the coral reef. Typically the lights need to be "burned in" for about one hundred hours before they are able to provide the adequate type of lighting for the coral reef. This is why new lamps can sometimes be unstable or vary in color. Many manufacturers "burn-in" their bulbs before they are sold. As the lamps age, changes occur in the lamp that cause shifts in the chromaticity of the lamps.
Generally, over the life of the lamps, they will shift in color temperature by a large amount. As a group of lamps age together in a coral reef tank, the lamps will generally shift at the same rate causing very little color variation from lamp to lamp. However, if new replacement lamps are introduced into the group of lamps, color differences may be more noticeable, because the new lamps have not aged and shifted with the remainder of lamps. The coral reef reacts in different ways depending on hoe drastic the change is.
