|It is normal for algae to begin growing back in an aquarium within three
weeks after it has been cleaned. To cut down on excessive growth, keep in
mind that light and nutrients in the water are the major causes of algae
growth. There are several ways that you can keep the re-growth of algae in
your aquarium under control.
First of all, do not overfeed the fish. Food that isn't eaten eventually
settles among the substrate and begins to break down to a form of detritus.
Organic material left in the tank provides essential nutrients perfect for
algae to thrive on.
If a fish dies, be sure to remove it immediately. Decaying matter only
creates higher levels of nutrients in the water, which is also a
contributing factor of rapid algae growth.
Keep one or several pieces of rock or coral in your marine fish-only tank.
Allowing a controlled amount of algae to exist in the tank will provide
adequate competition for new algae growth.
If you use decorative coral, bleach the coral in your marine fish-only
tank; this should be done every other month rather than every month. This
schedule is based on the same principle as leaving some algae in the tank.
If you do not already have an external canister filter on your aquarium,
you may want to consider installing one. You can help prevent algae growth
by using large quantities of chemical removal material in these filters.
The use of protein skimmers in marine tanks also helps to reduce algae
growth in the aquarium.
Another possibly installation to your aquarium can include an ultraviolet
sterilizer. Besides controlling parasites in the water, these devices also
kill algae cells in the water before they can grow and eventually become a
problem in your tank.