Everyone wants a beautiful, clean aquarium set-up, and almost everyone runs into algae problems… and hopefully solutions. Amongst all the types of queries we receive at WetWebMedia.com, this is the single largest category of folks looking for help.
All viable systems will grow algae… and it's not entirely a "bad thing"… Algae is indicative of a healthy/viable environment, can help keep your water clean, even provide food for your livestock! But too much algae can be too much of a "good thing".
Are algae problems inevitable? Decidedly not! There are three general classes of approaches to avoiding algae proliferation, by Design, Stocking and Maintenance… You should avail yourself of all these three fronts in your algae battle plan.
Avoiding Algae Problems From the Beginning: By Design
What type of system do you have or want? A Fish-Only (FO), Fish with live rock (FOWLR), or a type of reef? As importantly, what are your goals with having this system? Maintenance? Growth? What are the optimal conditions for the kinds of life and how much you want to boost its growth? In particular, how much light is enough, optimal, too much to support or accelerate the photosynthetic life there?
For FO systems, there is only a consideration of what looks best to the aquarist, and you can avoid most algae growth by denying them necessary wavelengths of light, and/or intensity or duration. Simply have the non-full-spectrum lighting on when you're present, off at other times. Modern timers are great for this.
For FOWLR systems the photosynthetic life on the rock requires more light (time and brightness as well as full-spectrum quality). Here's where Regular Output to High Output to Very High Output Fluorescents (RO, HO, VHO) and Metal Halides come in handy, depending on the size/depth of your tank.
Lastly, reef systems have the highest demand for quantity and quality lighting. Still, many systems are over-lit, and inappropriately illuminated in terms of photoperiod. Many aquarists do not take advantage of timer and dimmer tools, turning all or most of their lighting on "full-blast" in the morning, all off at night… Due to physical properties of sunlight, water and rotation of the planet, the "light day" in the wild is quite different, with a bright period only at "high noon". Photosynthetic Corals, Sea Fans, Anemones and others can't "catch-up" as quickly as opportunistic algae in the use of this "extra" light.
Filtration is enough huge variable to consider in avoiding the "algae blues"… By utilizing a working protein skimmer, having complete biological filtration (including nitrification AND denitrification), and periodic use of chemical filtrants (like monthly use/replacement of activated carbon), you can score another battle in limiting essential nutrients.
Circulation and aeration are very important. Algae are easily out-competed, displaced in areas of brisk water movement. Position your water intakes, pumps, powerheads to provide complete and vigorous movement of water in your system.
Algae Competitors and Predators: Control of Algae Through Appropriate Livestocking
It seems simple but many folks don't consider using more desirable types of photosynthetic life to curtail algae growth by competing for available nutrients. Food, wastes, dissolving d?or all contribute fertilizer to your system… it's got to go somewhere. Having healthy live rock, macro-algae, other photosynthetic livestock to "use up" these nutrients and light goes a long way in combating algae problems. A very appropriate means of "fighting algae with algae", is to place some macro-algae in a designated, continuously-illuminated "algae filter" sump.
Actual predators of algae are many for most kinds. Though few things eat the Blue-Green Algae (which are actually Cyanobacteria), the "true" algae groups have many fish and invertebrate consumers. For filamentous Greens, the Lawnmower Blennies (Salarias sp. mostly), are excellent if you have a large enough system. Several Hermit Crabs, the Emerald Green (Mithrax) Crabs, Bristle-tooth (genus Ctenochaetus) and Sailfin Tangs (genus Zebrasoma) are excellent choices as well.
The Biggest, Best "Cleaner Upper". You!
Maintenance plays a very large part in preventing algae population explosions. There are a myriad of things you can and should do to minimize their presence.
Water changes are an easy way to dilute available nutrient. Such periodic changes should be done with a gravel vacuum to maximize removal of solids while turning the substrate over. And on the issue of water, do check your source water. Many tap-water sources contain high concentrations of phosphate… a real algae booster. A simple in-line filter can take care of this problem, or you may be a candidate for a reverse osmosis device… for your aquarium as well as your drinking and cooking use.
Mechanical filter media like pads and cartridges should be on your regular maintenance schedule for cleaning, as well as your protein skimmer contact chamber and collector cup. Keep these clean and they will serve you best.
Take it easy on feeding, and watch what you feed. Many algae problems are directly due to overfeeding, including the use of terrestrial greens as food. Remember everything you put in, eaten or not, potentially feeds pest algae.
There are many steps you can take to prevent algae problems in your system, via initial design/set-up, what life you place in your tank, and how you go about its ongoing management. My best advice is use all three approaches. Prevent and fight algae problems through appropriate design, stocking and maintenance procedures.Bibliography/Further Reading:
Black, Tom & Alex Bielawski. 1971. Algae culture. Marine Aquarist 2(2):71.
Blackburn, Wayne. 1989. Plants in the marine system.
Delbeek, J.Charles. 1987. The role of symbiotic algae in marine invertebrates. FAMA 11/87.
Dewey, Don. 1979. Marine algae, a key ingredient to the successful saltwater system, part 1,2, introduction and cultivation of marine algae in the aquarium. FAMA 8,9/79.
Emmens, C.W. 1991. Algae. FAMA 8/91.
Fenner, Bob 1989. Some notes on algae and their control. FAMA 6/89.
Fenner, Robert. 1990. Ornamental marine algae; how to raise and market it., Macroalgae for marine aquaria. The Pet Dealer 2,10/90.
Fenner, Bob. 1991. Waterscape Maintenance: Copper Algicide Use in Pools. Freshwater and Marine Aquarium. 6/91.
Fenner, Robert 1998. The Conscientious Marine Aquarist. Microcosm, VT. 432pp.
Fenner, Bob. 1999. Frequent partial water changes. FAMA 5/99.
Fenner Robert. 2001. Blue-Green Algae (Cyanobacteria) in Marine Aquaria. SeaScope vol. 18, Winter 2001.
Frank, Neil. 1986. Algae in the aquarium; part II: strategies for control. FAMA 11/86.
Gamble, Sam. 1995. Algae curse: a new view. FAMA 8/95.
Glodek, Garrett. 1993. A lesson in plant taxonomy and systematics. FAMA 11/93.
Graff, Rick. 1993. Getting control of micro algae; how to deal with this problem in reef tanks. AFM 1/93.
Hoff, Frank. 1985. Zooxanthellae. FAMA 11/85.
Marchant, Don A. 1992. Red hair and hair algae madness. FAMA 2/92.
Michael, Scott. 1995. All that algae; if it makes you feel any better, this is a common problem.
Mowka, Edmund J. 1979. Water changes in the marine aquarium; partial water changes in the marine system are often neglected for a variety of reasons. Here's why water changes are essential, as well as a method of calculating the necessary amount. FAMA 12/79.
Olenik, J.E. with Mike Hoffer. The advantages of marine flora; the living flora that establishes itself in aquaria helps keep marine life healthy and makes the aquarium attractive. Here's a guide to the plants. Pets Supplies Marketing 4/91.
Paletta, Michael. 1990. Eliminating problem algae. Seascope, Aquarium Systems. Vol. 7, Fall 90.
Prasek, Edward D. 1995. Micro and slime algae: are they driving you crazy too? TFH 7/95.
Sands, David. 1994. Superb surgeons. FAMA 10/94.
Tullock, John. 1988. Zooxanthellae: symbiotic algae in invertebrates. Marine Fish Monthly 3(8)/88.
Wecsler, Lawrence H. 1975. Algae in the marine aquarium. TFH 2/75.