Here are a few reasons why you may have algae growing in your tank.

• You overstocked your saltwater aquarium with too many fish

• You have low circulation that does not properly oxygenate the water or hold debris in suspension long enough to be removed by the filters

• You overfeed your saltwater fish, uneaten food adds nitrate and phosphates to the water which fuel algae growth
• You used undersized filters and protein skimmers when you set your tank up
• Your light bulbs need to be replaced, old light bulbs shift to in light spectrum to a range that algae loves
• You do not keep up with normal required tank care like water changes
• You are not cleaning and changing filter material at normal intervals
• You maybe over using additives in the tank, never add anything you cannot test for or are unsure if you need it
• You are using tap water for your tank. Tap water is naturally full of nitrates and worse ye phosphates use reverse osmosis or deionized water instead
• You use a low quality salt mix that may have heavy metal or other impurities in i that can lead to algae blooms

For information on a few of the different types of algae and how to remove them from your fish tank, please take a few minutes to read the Types of Algae and how to take care of it article. You will find there are many easy things you can do to help with your algae problems.