Although
algae are often a source of great frustration for aquatic gardeners,
they need not be. What can at first seem like an unbeatable scourge
can in most cases be easily managed. But very rarely is any tank
algae-free. Some green spot algae on the aquarium glass or barely
discernable fuzz here and there are normal and nothing to be concerned
about. That is not to say that anyone should have to “live
with” an overabundance of the stuff!
As I touched upon a few months ago, balance is the word to remember
in planted aquariums. Besides helping plants to grow at their best,
maintaining proper nutrient levels in relation to other parameters
will discourage algae. Limiting nitrates and phosphates to almost
undetectable levels is a common beginner practice but not a good
idea and will often cause problems (like nutrient deficiencies)
that are just as bad if not worse than those that arise when nutrients
are in excess. Cyanobacteria and staghorn algae especially love
nutrient poor conditions. Other nutrients deserve attention too,
of course, and so I suggest the levels outlined in previous articles.
Look at the whole picture over the long run rather than, for example,
only nitrates or carbon dioxide. Test often with good kits until
you start to get an eye for things and regularly thereafter to make
sure everything is ok.
If algae do start appearing in excessive amounts, work to return
things to appropriate levels, whether by water changes or the addition
of whatever is in short supply. Be patient. Some algae take some
time to disappear after conditions are corrected. If it’s
possible, you may wish to manually remove some to speed everything
along.
Herbivores can be used to mop up what little algae remains in a
well-run tank. However, they can’t work miracles and are not
the first line of defense against algae. New tanks, on the other
hand, often have more than their fair share of algae until conditions
stabilize, and that is when algae consumers are needed the most.
Siamese algae eaters (Crossocheilus siamensis) do a decent
job of consuming hair and thread algae and may even eat black brush
algae. There are several similar cyprinids that are not as effective
in that role but sold as the real thing, so be sure to find a good
photograph on which to base any purchases (the photo in Baensch
is incorrect). American Flag fish (Jordanella floridae)
also remove a good bit of hair algae but may or may not be a bit
nippy. As I touched on previously, both might damage fine leaved
plants, so keep an eye on them. Otocinclus species are great consumers
of diatoms and short fuzz, and most won’t harm the plants.
The common species usually seen in aquarium stores (probably O.
affinis) is ideal. Another good herbivore is the shrimp made
famous by Takashi Amano, Caridina japonica. They are needed
in relatively large numbers to do the job, but are very thorough
and fun to watch. You must make sure there are no openings in the
canopy large enough for them to climb through. Keep them with small
fish only.
If worse comes to worse, turning off the lights and co2 along with
covering the tank with blankets for 2-4 days can be effective. Although
many plants will look a bit sickly after such a treatment, most
will recover. Algae rarely survive a few days of darkness. Upon
the end of the blackout, correct any nutrient imbalances and resume
normal tank maintenance.
Here are several methods of controlling algae that I do not recommend.
Don’t use algaecides. There is no such thing as an algaecide
that will kill algae and not damage plants, despite what labels
say. Damage to plants just doesn’t show up as quickly.
Don’t cut back on the duration of light. Ten to twelve hours
of light should be provided every day. Cutting back on that is a
mistake. Doing so will do more harm than good, as it will usually
weaken the plants and cause an even greater imbalance, thereby making
things worse. The same goes for splitting up the photoperiod, which
is very unnatural doesn’t offer any actual advantage.
Don’t automatically assume that the intensity of light is
too great. There may indeed be too much. But…it’s usually
the case that there is too much light in relation to the tank conditions.
Remember that high light levels require more carbon dioxide and
more careful nutrient management. Say, for example, that everything
else being equal and appropriate, one 50 gallon tank has three watts
per gallon of power compact fluorescent lighting and no carbon dioxide
supplementation while another does have co2. The first tank could
be said to have “too much light” while the second could
not. For a lower light tank without co2, that is usually not a problem.
Again, simply maintain nutrients in their proper ranges.
Some people recommend putting all new plants through a dip of one
part bleach to 19 parts water for a few minutes before adding them
to the tank. I don’t recommend doing that. Tougher plants
can survive without a problem, but more delicate species can suffer
badly and not revive. More importantly, the whole procedure is totally
unnecessary. If conditions aren’t right for a particular species
of algae to grow, it won’t. It’s that simple. Introduce
any of them to a smoothly running tank with good conditions and
they won’t spread. Strongly growing plants equal very little
algae.
Now that we’re done with the nitty gritty, we’ll move
on to the merits and uses of various aquarium plants.
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