Modern algae scrubber designs use upflowing air bubbles to generate turbulence; when illumination is added, algae grows inside the unit and consumes nutrients. Commercial floating surface algae scrubber uses red LED lights and up-flowing air bubbles to cause algae to grow in the growth compartment. Inside of the compartment is lined with rough textures which enhance algal attachment; ribbons/strings allow further algal attachment. Periodic removal of the algae that has grown inside of an algae scrubber removes nutrients (ammonia, nitrate, phosphate) from the aquarium water, thus providing the needed filtration. An algae scrubber is a water filtering device (not to be confused with a scrubber pad used to clean glass) which uses light to grow algae; in this process, undesirable chemicals are removed from the water. Nutrient Cycling In The Great Barrier Reef Aquarium. Proceedings of the 6th International Coral Reef Symposium, Australia, 1988, Vol. 2 Algae scrubbers allow saltwater, freshwater and pond hobbyists to operate their tanks using natural filtration in the form of primary production, much like oceans and lakes. Concepts An algae scrubber filters water by moving water rapidly over a rough, highly illuminated surface, which causes algae to start growing in large amounts. As the algae grow, they consume nutrients such as nitrate, phosphate, nitrite, ammonia, ammonium and even metals such as copper from the water. Algal Response To Nutrient Enrichment In Forested Oligotrophic Stream. Journal of Phycology, June 2008 These nutrients are normally a problem in aquariums and ponds because they cause nuisance algae to grow, and also because they cause sickness and/or other problems in aquarium fish, invertebrates and corals. Fish Disease: Diagnosis and Treatment, Second Edition, 2010 An algae scrubber allows algae to grow, but the algae grow inside the filter instead of in the aquarium or pond. This removes excess nutrients (scrubs the water), diminishing nuisance algae in the aquarium or pond . Nuisance algae in the aquarium or pond are not to be confused with the desired algae in the algae scrubber filter itself. The algae that grow in the algae scrubber can then be removed, or fed back to the livestock. Both iron fertilization and ocean nourishment are techniques that boost the primary production of algae in the ocean, which consumes massive amounts of nutrients and CO2 . It is this same consumption of nutrients that algae perform in an aquarium or pond. The algae scrubber was invented by Dr. Walter Adey, who beginning in the late 1970s, was Director of the Marine Systems Laboratory at the Museum of Natural History, Smithsonian Institution (Washington DC, USA). Smithsonian Institution, Dept. of Botany His research of various types of algae, especially in their ecological role on coral reefs, gave him insight into how the ocean (in particular a reef) "recycles" nutrients. He designed and built various exhibits ranging in size up to 3000 gallons, and modeled different aquatic ecological systems including a tropical coral reef/lagoon which "after 8 years of closure [to the environment], had its chemical parameters controlled solely by an algal turf scrubber. This system, studied by a multidisciplinary team of biologists, demonstrated calcification [coral growth] rates equal to the best 4 percent of wild reefs, and at 543 identified species, and an estimated 800 species, ranked per unit area as the most biodiverse reef ever URL Unfortunately, it was not known at the time (1988) that calcium and alkalinity needed to be added to an enclosed reef tank, in order to replace that which is utilized by the growing calcifying organisms. Even five years after that, the Pittsburgh Zoo was just starting to test a "mesocosm" scrubber reef tank to see if calcium levels would drop: "It was hypothesized that Ca2+ and the substitutive elements Sr2+ and Mg2+ might have reduced concentrations in a coral reef microcosm due to continuous reuse of the same seawater as a consequence of the recycling process inherent in the coral reef mesocosm." [...] "The scleractinians (Montastrea, Madracis, Porites, Diploria, and Acropora) and calcareous alga (Halimeda and others) present in the coral reef mesocosm are the most likely organisms responsible for the significant reduction in concentration of the Ca2+ and Sr2+ cations." [...] "Ca is not normally a biolimiting element, and strontium is never a biolimiting element; HCO3 [alkalinity] can be. It appears that, because of a minor limitation in the design parameters of the mesocosm, these elements and compounds may have become limiting factors. [...] It is surprising that the organisms could deplete the thousands of gallons of seawater (three to six thousand) of these elements even within two or more years." An Introduction to the Biogeochemical Cycling of Calcium and Substitutive Strontium in Living Coral Reef Mesocosms URL After other researchers added calcium and/or connected their tanks to the ocean (which also supplies calcium and alkalinity), corals began growing again. Nevertheless, "problem" nutrients (ammonia, ammonium, nitrate, nitrite, phosphate, CO2 , metals) were always kept at very low numbers. Interest in using algae for nutrient control once again increased, this time in the form of keeping the algae in a "sump" or other small aquarium which was connected to the main aquarium via plumbing. With added lighting and flow, algae would grow in this area, and the algae would consume nutrients from the water just as Dr. Adey's algae scrubber units did. Sumps or other small aquariums used for this purpose became known as "refugiums". Reef Invertebrates, 2003, page 46 The name "refugium" was used because the growing algae provided a safe place for small and microscopic animals to breed and grow, and thus was a "refuge" from the large fish and invertebrates in the main aquarium that would otherwise consume them. However while the refugiums did indeed consume nutrients from the water, they did not consume them fast enough in all situations; this caused many hobbyists to continue to have nuisance algae problems in their main aquariums. In addition, "turf" algae, which was the focus of Dr. Adey's dumping-bucket design, is replaced by "green hair algae".AlgaeScrubber.Net This is because turf algae tends to be dark brown and thick (like artificial turf on sports fields), and it blocks the light and water from reaching the screen. This slows the growth (and filtering) of the algae because the bottom layers of algae that are attached to the screen start to die and detach. Green algae, however (especially light-green hair algae), allows light and water to penetrate all the way down to the screen if the growth is kept less than 20 mm thick, Production within dense mats of the filamentous macroalga Chaetomorpha linum in relation to light and nutrient availability, figure 5. URL which allows the algae to grow faster and absorb more nutrients without dying and losing attachment to the screen. This is fortunate because green hair algae is the exact type of algae that grows automatically in a properly constructed algae scrubber.
Modern algae scrubber designs use upflowing air bubbles to generate turbulence; when illumination is added, algae grows inside the unit and consumes nutrients. Commercial floating surface algae scrubber uses red LED lights and up-flowing air bubbles to cause algae to grow in the growth compartment. Inside of the compartment is lined with rough textures which enhance algal attachment; ribbons/strings allow further algal attachment. Periodic removal of the algae that has grown inside of an algae scrubber removes nutrients (ammonia, nitrate, phosphate) from the aquarium water, thus providing the needed filtration. An algae scrubber is a water filtering device (not to be confused with a scrubber pad used to clean glass) which uses light to grow algae; in this process, undesirable chemicals are removed from the water. Algae scrubbers allow saltwater, freshwater and pond hobbyists to operate their tanks using natural filtration in the form of primary production, much like oceans and lakes. Concepts An algae scrubber filters water by moving water rapidly over a rough, highly illuminated surface, which causes algae to start growing in large amounts. As the algae grow, they consume nutrients such as nitrate, phosphate, nitrite, ammonia, ammonium and even metals such as copper from the water. These nutrients are normally a problem in aquariums and ponds because they cause nuisance algae to grow, and also because they cause sickness and/or other problems in aquarium fish, invertebrates and corals. An algae scrubber allows algae to grow, but the algae grow inside the filter instead of in the aquarium or pond. This removes excess nutrients (scrubs the water), diminishing nuisance algae in the aquarium or pond . Nuisance algae in the aquarium or pond are not to be confused with the desired algae in the algae scrubber filter itself. The algae that grow in the algae scrubber can then be removed, or fed back to the livestock. Both iron fertilization and ocean nourishment are techniques that boost the primary production of algae in the ocean, which consumes massive amounts of nutrients and . It is this same consumption of nutrients that algae perform in an aquarium or pond. The algae scrubber was invented by Dr. Walter Adey, who beginning in the late 1970s, was Director of the Marine Systems Laboratory at the Museum of Natural History, Smithsonian Institution (Washington DC, USA). His research of various types of algae, especially in their ecological role on coral reefs, gave him insight into how the ocean (in particular a reef) "recycles" nutrients. He designed and built various exhibits ranging in size up to 3000 gallons, and modeled different aquatic ecological systems including a tropical coral reef/lagoon which "after 8 years of closure [to the environment], had its chemical parameters controlled solely by an algal turf scrubber. This system, studied by a multidisciplinary team of biologists, demonstrated calcification [coral growth] rates equal to the best 4 percent of wild reefs, and at 543 identified species, and an estimated 800 species, ranked per unit area as the most biodiverse reef ever measured." Unfortunately, it was not known at the time (1988) that calcium and alkalinity needed to be added to an enclosed reef tank, in order to replace that which is utilized by the growing calcifying organisms. Even five years after that, the Pittsburgh Zoo was just starting to test a "mesocosm" scrubber reef tank to see if calcium levels would drop: "It was hypothesized that and the substitutive elements and might have reduced concentrations in a coral reef microcosm due to continuous reuse of the same seawater as a consequence of the recycling process inherent in the coral reef mesocosm." [...] "The scleractinians (Montastrea, Madracis, Porites, Diploria, and Acropora) and calcareous alga (Halimeda and others) present in the coral reef mesocosm are the most likely organisms responsible for the significant reduction in concentration of the and cations." [...] "Ca is not normally a biolimiting element, and strontium is never a biolimiting element; [alkalinity] can be. It appears that, because of a minor limitation in the design parameters of the mesocosm, these elements and compounds may have become limiting factors. [...] It is surprising that the organisms could deplete the thousands of gallons of seawater (three to six thousand) of these elements even within two or more years." After other researchers added calcium and/or connected their tanks to the ocean (which also supplies calcium and alkalinity), corals began growing again. Nevertheless, "problem" nutrients (ammonia, ammonium, nitrate, nitrite, phosphate, , metals) were always kept at very low numbers. Interest in using algae for nutrient control once again increased, this time in the form of keeping the algae in a "sump" or other small aquarium which was connected to the main aquarium via plumbing. With added lighting and flow, algae would grow in this area, and the algae would consume nutrients from the water just as Dr. Adey's algae scrubber units did. Sumps or other small aquariums used for this purpose became known as "refugiums". The name "refugium" was used because the growing algae provided a safe place for small and microscopic animals to breed and grow, and thus was a "refuge" from the large fish and invertebrates in the main aquarium that would otherwise consume them. However while the refugiums did indeed consume nutrients from the water, they did not consume them fast enough in all situations; this caused many hobbyists to continue to have nuisance algae problems in their main aquariums. In addition, "turf" algae, which was the focus of Dr. Adey's dumping-bucket design, is replaced by "green hair algae".AlgaeScrubber.Net This is because turf algae tends to be dark brown and thick (like artificial turf on sports fields), and it blocks the light and water from reaching the screen. This slows the growth (and filtering) of the algae because the bottom layers of algae that are attached to the screen start to die and detach. Green algae, however (especially light-green hair algae), allows light and water to penetrate all the way down to the screen if the growth is kept less than 20 mm thick, P which allows the algae to grow faster and absorb more nutrients without dying and losing attachment to the screen. This is fortunate because green hair algae is the exact type of algae that grows automatically in a properly constructed algae scrubber.
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Nutrient Cycling In The Great Barrier Reef Aquarium. Proceedings of the 6th International Coral Reef Symposium, Australia, 1988, Vol. 2
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Algal Response To Nutrient Enrichment In Forested Oligotrophic Stream. Journal of Phycology, June 2008
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Fish Disease: Diagnosis and Treatment, Second Edition, 2010
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CO2
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Smithsonian Institution, Dept. of Botany
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URL
measured."
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Ca2+
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Sr2+ and Mg2+
and
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Ca2+ and Sr2+
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HCO3
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An Introduction to the Biogeochemical Cycling of Calcium and Substitutive Strontium in Living Coral Reef Mesocosms URL
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CO2
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Reef Invertebrates, 2003, page 46
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Production within dense mats of the filamentous macroalga Chaetomorpha linum in relation to light and nutrient availability, figure 5. URL
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