Salt Water Aquarium Tips and Tutorials

How do you get rid of green algae in a salt water aquarium?

I have a 65 gallon salt water aquarium that keeps getting that awful green algae on the rocks & bottom of the tank. I have cut down the time that the light is on, bought more snails & that still hasn’t helped.

Add natural algae eating critters. Various forms of green, brown and red algae can provide browsing food for many types fish and inverts, and many macroalgae species are actually cultivated in the aquarium for this purpose. There are a lot of marine inhabitants that depend on algae as a major part of their diets. Tangs and Surgeonfishes of the Zebrasoma & Ctenochaetus species, and most Angelfishes are prime examples.
If your fish friends can’t keep up with the algae growth, you can periodically harvest it to keep it in check without completely eradicating it from your system. Introducing additional herbivores like Snails and Hermit Crabs, as well as detritivores like Starfishes, Cucumbers and Marine Worms are all greatly beneficial. Just be sure to get the correct types that will eat the kind of algae you are dealing with.
Grow some competitive macroalgae. In Robert Fenner’s (author of The Conscientious Marine Aquarist) WetWebMedia Green Algae-The Chlorophyta article he discusses both good and pest types of macroalgae. Under the Benefits – Algae Control section he points out that by growing an initial batch of algae, this in turn can "limit" the growth of unwanted pests types like slime, hair, fungus and bacteria forms. Because all algae compete for the same light, nutrients and space that is available in an aquarium, the growth of a good type of competitive macroalgae deprives the pest types of these elements to grow aggressively.

What are the best "starter" fish for a salt water aquarium?

December 28th, 2007 at 8:36 pm


8 Responses to “How do you get rid of green algae in a salt water aquarium?”

  1. Jade s Says:

    scrub it! or get a fish who eats that
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  2. Nikki M Says:

    one word: filter
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  3. princess_sam_21 Says:

    Add natural algae eating critters. Various forms of green, brown and red algae can provide browsing food for many types fish and inverts, and many macroalgae species are actually cultivated in the aquarium for this purpose. There are a lot of marine inhabitants that depend on algae as a major part of their diets. Tangs and Surgeonfishes of the Zebrasoma & Ctenochaetus species, and most Angelfishes are prime examples.
    If your fish friends can’t keep up with the algae growth, you can periodically harvest it to keep it in check without completely eradicating it from your system. Introducing additional herbivores like Snails and Hermit Crabs, as well as detritivores like Starfishes, Cucumbers and Marine Worms are all greatly beneficial. Just be sure to get the correct types that will eat the kind of algae you are dealing with.
    Grow some competitive macroalgae. In Robert Fenner’s (author of The Conscientious Marine Aquarist) WetWebMedia Green Algae-The Chlorophyta article he discusses both good and pest types of macroalgae. Under the Benefits – Algae Control section he points out that by growing an initial batch of algae, this in turn can "limit" the growth of unwanted pests types like slime, hair, fungus and bacteria forms. Because all algae compete for the same light, nutrients and space that is available in an aquarium, the growth of a good type of competitive macroalgae deprives the pest types of these elements to grow aggressively.
    References :
    http://saltaquarium.about.com/cs/algaecontrol/a/aa111797algae_2.htm

  4. quackie81 Says:

    try buying a janitor fish, it really helps, but i don’t think it can live on a salty environment
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  5. 007 Says:

    Try adding about 30 small blue leg hermit crabs, 1 or 2 emerald crabs, Red sea star…they graze all day on different algae.
    Depending on the fish that you already have, You MAY be able to add a Tang, they love grazing on green algae.
    If your tap water is anything like mine, There is lots of phosphates in it so I do topups and partial water changes with RO/DI water.
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  6. mlsbutterfly26 Says:

    I agree with the other 2 posts I have a 60gal tank that had the same problem. I increased the number of blue hermit crabs and I have a much smaller algae problem. I use an aquarium vacuum to get the green and red algae that occasionally starts to develop in the sand
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  7. copperhead Says:

    First, you should be certain that what you’re dealing with in your tank is green algae, not a green cyanobacteria – see photo for comparison: http://www.aquamax.de/Shop/Artikelbilder/Zusatzbilder/Algen%20im%20Aquarium_Blaualgen%20-%20Cyanobacteria_STUG_cyano1.jpg

    Cyanobacteria isn’t an algae, but a BACTERIA! A more common type of this in a saltwater tank is the "red slime" – also a bacteria. Because these are bacteria, not an algae (although they were once called blue-green algae for their appearance, this is no longer correct), traditional algae remedies don’t always work to remove them. Chemical means should be avoided, because these will disrupt your beneficial bacteria as well, leaving you to have to cycle your tank again and your tank inhabitants in higher ammonia/nitrite levels while the bacteria repopulate. Here’s a Bob Fenner article for control of the cyano, in case that’s what you have in your tank: http://saltcorner.com/sections/guest/algaepage/algaepage.htm

    Since both algae and cyanobacteria need nutrients to grow, try more frequent water changes, and possibly use a phosphate pad to adsorb phosphates in your tank as well as the other control measures.
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  8. Brian Says:

    Agae lives off three things. Nitrates, phosphates, and light. Starving it of its nutrients is the best way to control it. If you are using tap water it is loaded with nitrates and phosphates. Yes federal regulations limit those but test yours yourself sometime and you will notice they aren’t always within the allowed limits.

    Use only DI/RO/distilled water for saltwater. This will ensure you do not add in any nitrates or phosphates to your tank. Change your water often enough to stay less than 10 ppm nitrates and 0 phosphate. Personnally I think 10% weekly is plenty to accomplish this unless you have a a very high bioload in your tank.

    Use your daylight lighting a maximum of 8 hrs per day and your actinics a max of 10 hrs per day. Nothing in your tank besides algae needs more than this. If you only have 1 light source 10hrs is more than enough for your tank. If you have corals I assume you know their lighting needs and will stick to those.

    Phosphate removing pads and media will help but unless you remove the source of the phosphates you must continue that treatment. The pure water for water changes will take care of that problem much cheaper.

    If you have a sump you can add in a small cheap light and grow various macro algae(seaweed) in it which works as a nitrate removal system. Another alternative is to use a macro algae in the tank itself. I gorw some very nice red macroalgae that I use in my tanks not only for nitrate absorbtion but also for decoration.

    If you have live rock the coralline will compete with the algae for nutrients as well. Adding one small piece of live rock will seed the coralline algae to grow. Once it takes over you have some very nice purple and red encrusting coralline instead of unsightly green and brown hairy junk.

    The snails and crabs are very important to your filtration of a saltywater tank but not the best for algae removal. Taking out the source of the algae is the best option. If you have a few snails, crabs and some live rock combined with using only pure water for water changes you will have a very maintenance free tank. Everything else will work for you in keeping it clean.
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