Ask any reef keeper their thoughts on algae, and they will undoubtedly respond with a mixed bag of emotions. Algae is both a food that nourishes corals on a microscopic scale as well as the dreaded weeds that we all have to deal with shading out our corals on a macro scale. It is the very plant that can release toxins to prevent coral growth and also the thing that can help us remove harmful nutrients that impede coral growth. Chaetomorpha algae, if used in the reef aquarium properly, can have the latter of these effects. It is fairly unique in that it can reduce nitrates and phosphates as well as provide a home for a whole world of life that helps sustain the rest of the marine organisms that are kept in a reef aquarium.
What is Chaetomorpha?
Chaetomorpha is a single celled algae that lives in many habitats of the ocean around the world. Its growth form resembles a corkscrew of strings and looks much like a piece of steel wool or pasta. The most common species of Chaetomoprha or Chaeto (pronounced cato) as it is often called is Chaetomorpha linum. Chaeto is different than most other algae that are grown in reef aquariums in two ways. First, they are made up of single tubular strands of cells that are connected end to end which makes them fast growing and increases their surface area very quickly. Second, they do not contain the turpin compounds that most other macro algae have. The lack of these turpins and thus the inability to slow coral growth make these algae the preferred type to use in a reef aquarium or refugium.
Can Chaetomorpha help reduce Nitrates and Phosphates?
Perhaps the characteristic that makes Chaeto most desirable to the home reef aquarist is its ability to sequester nitrates and phosphates into its cell structure. Thus a simple way to remove these unwanted compounds from the reef aquariums is to simply remove handfulls of Chaeto from time to time. This makes a great cheap and simple alternative to many of the absorbing medias, chemicals, as well as reducing the frequency of water changes. Just think about how much you spend on these products and maybe you will find some value in using that money to setup a small refugium with a light.
How and where to grow Chaetomorpha
All that you need to get a nice stand of Chaeto growing in your aquarium, sump, or refugium is a moderate amount of flow, decent lighting, and a handful of Chaeto from your local fish store. If it is not possible to have a moderate water flow, you can simple shake or rinse off the Chaeto in saltwater from time to time to removes all the detritus. This will also spread out the Chaeto so that it can get light and grow more vigorously. It is not necessary or reccomended to feed or fertilize this algae as it will get all the nutrients it needs from the nitrates and phosphates in the water.
Other benefits of Chaetomorpha
Besides providing a simple and inexpensive way to export nitrates and phosphates from the marine aquarium, Chaeto also has some side benefits. The dense mat that this algae forms becomes a suitable home for all sorts of amphipods, copipods, and other marine zooplankton. These zooplankton will slowly drift thir way into the reef aquarium where they can be food for the corals, fish, and other creatures. A good way to also transport these organisms from the algae to the reef aquarium is to simply shake off the handfulls of Chaeto that you remove for the nitrate and phosphate removal into the main aquarium before you dispose of them. This live and seemingly endless buffet of zooplankton will enhance both size and coloration of your reef creatures over time.