Nuisance Algae
by Aquariumpros.com staff
Reprinted with permission
http://www.aquariumpros.com/company
Aquarticles
Algae (Plural: Algae / Singular: Algae or Alga) is
the bane of every aquarium owner. Algae grows in every healthy aquarium, no matter how
well, or how often the tank is cleaned. There is absolutely no safe way to completely
prevent or stop the growth of algae. Once it starts to grow in an aquarium, it does so
very rapidly. A small patch of algae can triple in size in a few days. When one of our
clients calls and informs us that their aquarium is "dirty", we know
they’re referring to algae growth on the tank, or on the gravel or decorations.
Algae and "That Other Slimy Stuff"
There are many types of algae. There are also a few organisms that look like algae but are
not algae at all. In a healthy aquarium, the algae will be green, and if left alone, will
grow hair-like in appearance. Algae that is red or brown may indicate a water quality
problem, such as high dissolved nitrate or phosphate levels in the water. Red and brown
algae are also common in new tanks, when the aquarium is not yet ecologically balanced.
These types of algae are also quite common in saltwater fish-only tanks when the coral
decorations are cleaned on a regular basis. The small round green "dots" that
form on the sides of a tank are not algae. These are actually populations of Diatoms,
microscopic animals that secrete a hard calcium shell on which green algae grows. This
type of "algae" is the most difficult to remove.
An aquarium may occasionally break out with an infestation of cyanobacteria, a slimy
growth that grows more rapidly than algae. It may be green, blue, black or red in color.
Unlike algae, cyanobacteria is extremely easy to remove but very difficult to control.
Even if every bit is removed, it can quickly grow back in only a few days. Cyanobacteria
thrives in well-lit aquariums that have excessive levels of phosphate in the water.
Cyanobacteria can also plague marine aquariums in which the coral is cleaned frequently.
In order to bring cyanobacteria under control, the aquarium must be cleaned thoroughly.
The amount of light the tank receives is dramatically reduced for several weeks. An
organic chemical such as Boyd's Chemi Clean is also added to the water to inhibit the
growth of cyanobacteria. Several treatments may be necessary before the problem is brought
under control.
Although it’s rather unattractive, algae is not "dirt", but a primitive
form of plant-like life. Green and some brown algae growth is normal and natural and
occurs in nearly all aquariums. Like plants, all species of algae need light, water and
nutrients to grow. Since an aquarium provides the water, we’re left with two factors
that you can control to prevent the rapid accumulation of algae. These are: the amount of
light the aquarium receives; and the levels of nutrients dissolved in the water. There are
also tap water pretreatment, filtration and sterilization methods that can tremendously
reduce the growth rate and accumulation of algae.
Lighting:
Limiting the light that the aquarium receives is the most important factor in controlling
algae growth. If an aquarium is near a window, algae will grow faster, even if the
aquarium does not receive direct sunlight. Leaving the aquarium lights on for more than
eight hours a day can also cause rapid algae growth. We suggest that the aquarium be
placed as far away from a window as possible. If an aquarium must be placed near or facing
a window, blinds or drapery should be kept closed during the day. The aquarium lights
should not be on for more than ten hours a day. Fish require no less than six hours of
light every day in order to manufacture vitamin D. They also must have consistent
lighting, with the lights coming on and going off at the same times every day.
We recommend that the tank lights be controlled by a timer. It is ok to adjust the
aquarium lighting to coincide with your schedule, so you can enjoy the aquarium when
you’re home, provided the lighting time period (photoperiod) is always consistent. If
the light timer is set to come on in the afternoon, and go out late at night, the amount
of ambient daylight the aquarium receives should be limited by closing blinds or drapes
during the day. The light timer should be set to come on an hour before you get home, and
to go off an hour after you go to bed. The aquarium lights should never be set to come on
and off more than once a day. Please remember that fish should be fed twice a day. Fish
will not feed in a dark aquarium. If the lights are set for an afternoon/evening cycle,
feed the fish once when you get home, and once again before you retire for the evening.
Nutrients:
Like any plant, algae require food to survive. The three main nutrients that algae need
are nitrogen, phosphorus and potassium. In an aquarium, these nutrients come from fish
waste, uneaten food, the metabolism of beneficial bacteria, and the decay of other
organics such as plant debris or even dead algae. There is also a surprisingly high amount
of phosphorus in our tap water. You control the accumulation of nitrogen when you perform
a water change. Phosphates may be controlled by using phosphate-removal media in an
external filter or by using reverse osmosis water for the aquarium.
Cleaner Tanks Grow Algae Faster!
This is a difficult concept to understand. It is important to remember that algae growth
is a natural, normal process in any aquarium. All aquariums grow algae in one form or
another. Some algae grows naturally in all ponds, lakes, rivers and oceans. If a section
of the ocean floor is swept completely clean of life by a hurricane, the first organism to
start growing back is algae. When you clean your aquarium and all of the decorations
thoroughly, you leave no algae behind. In this bright, squeaky-clean environment, algae
grows back more rapidly than it would if you left a small amount of algae somewhere in the
tank. This is especially true in saltwater aquariums, where the bright white coral and
gravel reflect more light, causing algae to grow faster. The reason for this is that if
there is no algae left in the tank, there is no competition for nutrients that the algae
feeds on. If you leave a few rocks or pieces of coral in a tank with a good growth of
algae on them, that algae will consume nutrients in the water, which helps to control new
growth.
The best way to illustrate this principle is to take a look at the two types of
aquariums that are rarely plagued with heavy algae growth. These are: freshwater aquariums
that are well populated with live plants; and saltwater live-coral reef aquariums. In
these aquariums, the plants in freshwater tanks, and the photosynthetic corals, anemones,
and other sessile invertebrates in reef tanks, compete with algae for light and nutrients.
As algae is a relatively primitive organism, it doesn’t stand a chance when competing
against the more advanced plants or photosynthetic corals in these types of aquariums. It
is actually better for your aquarium to allow some algae to exist somewhere in the tank,
especially if your aquarium has chronic algae problems.
What About Algae-Eating Animals?
In freshwater aquariums there are a few species of algae-eating fish and snails that can
help to keep algae under control. Freshwater snails can breed and over-populate a tank,
creating more of a nuisance than the algae they’re supposed to eat. The algae-eating
fish do not feed exclusively on algae, and if well-fed, will ignore the algae growing in
your tank. However, keeping one snail and/or a few small Plecostomus species of fish may
help to control algae in-between maintenance visits.
There are very few fish available for marine aquariums that will eat the algae that
grows in an aquarium. Certain tangs, parrotfish, and blennies will graze on some of the
algae, but not effectively enough to keep the tank clean. There are quite a few marine
invertebrates such as certain crabs, hermit crabs, snails and sea urchins that can eat a
lot of algae. Unfortunately, few of these invertebrates can be kept safely in the average
saltwater fish-only tank. These animals are the natural prey of many desirable saltwater
fish, and your fish would willingly eat many of these expensive "snacks" if
given the opportunity. These invertebrates can be kept in a marine living-coral reef
aquarium, where the fish are smaller omnivorous species that will leave them alone.
Our Wonderful Tap water (or Things You Don’t Want to Know)
Almost all municipal water treatment facilities treat our tap water to kill algae,
bacteria and protozoa before it is filtered and delivered to our faucets. Not all of the
chemicals that are used get filtered out. On any given day, our tap water may contain
fluoride, iodine, chlorine, chloramine, and traces of: potassium permanganate, magnesium
sulfate, nickel sulfate, copper sulfate, various heavy metal-nitrate complexes, as well as
pollutants such as lead, PCB, mercury, and silver nitrate. Yummy! More of these chemicals
are used during the fall and spring when temperature changes cause a phenomenon called
"Biannual Turnover". Temperature fluctuations cause the water at the bottom of
lakes to rise, carrying silt and anaerobic material up into the water collected for our
use. All of the chemicals used in tap water can be toxic to fish.
Although a good portion of our municipal plumbing systems have been modernized, nearly
all of them still have old lead pipes in-line which can create deadly high-lead levels in
our drinking water. The cost of replacing these pipes is astronomical, so another solution
was found. Several years ago, water treatment plants started introducing a phosphorus
compound into our tap water which binds to the lead in the pipes and coats them so that
lead does not get into our water. Unfortunately, this has had the bad side-effect of
creating rather high levels of phosphates in tap water. We have tested levels of over 0.50
parts per million in our tap water. Our test kits only measure up to 0.10 ppm, and we have
had to dilute our samples by as much as ten times to achieve accurate readings! This high
level of phosphates in the tap water has been a major cause of rapid algae growth in
aquaria for the last few years. We lower these levels considerably by using
phosphate-removal filter media in your external filter. However, every time you change the
water, you actually add more phosphates to the aquarium. If the city uses more phosphorus
from time to time, the algae can grow back almost immediately after your aquarium is
cleaned.
Special Equipment to Control/Prevent Algae Growth
The Aquarium Professionals Group has installed many state-of-the-art aquarium systems
which use various devices designed to prevent the growth of algae. Some of this equipment
is impractical or too expensive for the average aquarium owner. The various equipment
and/or techniques that can be used are: 1) Ultraviolet Sterilizers; 2) Ozonization; 3)
Reverse Osmosis; 4) Resin Exchange Filters; 5) Algae Scrubbers; and 6) Using Reverse
Osmosis, Bottled or Distilled Water for Water Changes.
The use of reverse osmosis water for the aquarium will prevent any excess phosphates or
other chemicals from getting in the aquarium, thereby helping to control algae.
What You Can Do to Help Prevent Algae Growth
It is normal for algae to begin growing back in an aquarium within three weeks after the
tank is cleaned. Please keep in mind that light and nutrients in the water are the major
causes of algae growth. There are several ways that you can help control the re-growth of
algae in your aquarium:
Don’t overfeed your aquarium.
If a fish dies, remove it immediately. Decaying matter creates high levels of nutrients
in the water, causing rapid algae growth.
Keep one or several pieces of rock or coral in your marine fish-only tank that is never
cleaned. Allowing a controlled amount of algae to exist in the tank will provide
competition for new algae growth.
If you use decorative coral, bleach the coral in your marine fish-only tank every other
month instead of every month. This works on the same principle as leaving some algae in
the tank.
If you do not already have an external canister filter on your aquarium, install one.
By using large quantities of chemical removal material in these filters, you can help
prevent algae growth. Protein skimmers in marine tanks also help to reduce algae growth in
the aquarium.
Unless your aquarium already has one, install an ultraviolet sterilizer on the tank.
Besides controlling parasites in the water, these devices also kill algae cells in the
water before they can grow in your tank.
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