Help! I have algae in my
pond! What do I do?
This depends on several factors:
Is it the algae suspended in the water, or is it attached to
surfaces?
- If you are unsure, get a clear
glass and fill it with pond water. If the
water looks green, then you
have a special condition called "Green
Water".
This is a tough condition
to treat, and we have a section below
dedicated
to this particular problem.
If your water is clear, continue
reading.
General Algae Control Methods
1.
Plant your pond and fertilize!
If you have algae in your pond, you likely have a lot of sun
on your pond. The general idea is to rob the
algae of its food source by having the plants take it up first.
It may seem counter-intuitive
to fertilize a plant that is trying to take up fertilizer,
but aquatic fertilizers are
different than your standard houseplant fertilizer.
They are made to anticipate the
existence of certain biological wastes like Nitrate and Phosphate. They add the
extra fertilization components to help plants build their leaves, stems, and flowers.
It's like trying to build a
house, but you only have lumber and bricks.
These would be like the
existing Nitrates and Phosphates in your pond. If you don't have the nails and
mortar, then you can't build a house. Aquatic
fertilizer is like the nails and the mortar.
There are a number of different types of algae and one of them is sure to grow
based on whatever is in your water.
They are simple organisms that have adapted to
less than ideal conditions. Plants, on the other hand, are more complex and
require specific nutrients. Give them that little
extra boost with aquatic fertilizer,
and they will suck up tons of organic waste that would otherwise feed your
algae.
2.
Use Barley Straw
Barley straw is commonly added to ponds to reduce algae
because it produces a natural algaecide as it decays.
Barley straw comes in a number of forms:
bales, pellets, and pre-formed
planters so that you can disguise them as a natural pot for a plants. Each of these
forms of barley must decay over a period of several weeks to produce algaecide.
In Arkansas these barley bales
or pellets must be replaced 2-3 times in a season. One should put in one
bale early in the spring, and then about 4 weeks before changing it, put in a second
one so that the decay process can catch up.
Barley is also available in a ready
to go liquid form that does not require time to break down. This is often
combined with peat extract which adds a tiny bit of tint to the water (about the consistency
of light tea) to help block the sunlight that feeds algae. The plus to this
method is that it works far more quickly, but it must be added weekly whereas the barley
bales only need to be swapped a couple of times in the whole season. Some
people who get a late start on using barley bales will often combine the liquid
and the bales until the bales have started to decay.
Why is my pond water green?
"Green Water", a condition that causes a pond to look like it is
filled with pea soup, is caused by a unicellular algae that is
generally introduced from common tap water. When high nutrient
levels from overfeeding or infrequent water changes meet with
sunlight, Green Water is usually produced. Green Water
is a very tough condition to control once you have it. It is
far easier to prevent than it is to treat. Ironically, for a
water condition that looks so bad, it is not harmful to the fish.
The high nutrient levels that cause it, however, are harmful.
Prevention of Green
Water is simple.
1. Keep your
feeding to a minimum. Feed once every other day and do not
feed
more than the fish will consume
in 2 minutes.
2. Plant your
pond and keep your plants fertilized! If you have Green Water,
you likely have a lot of sun on
your pond. The general idea is to rob the Green Water algae of its food source by
having the plants take it up first.
3. Keep your nitrate levels low by doing periodic water
changes if you are unable to plant. The idea is to
change AT LEAST 30% of the water. At least 30% means that is the recommended minimum water needed to reduce the nutrient levels by a
significant amount. The way to tell how much water you should change is by testing
the nitrate levels in your pond. If the nitrates are higher than 40 ppm (parts per
million), you should do a larger water change.
NOTE: The recommendation
to change water is to reduce nutrient levels that feed the Green Water algae, NOT
to rid the pond of the Green Water directly.
Green Water algae
comes in via
tap water, so multiple water changes are, by definition, a self-defeating
"treatment". You
will need a mechanism of direct treatment to get rid of the Green Water.
The recommended treatment
for Green Water:
UV Sterilization
Green water often comes right back after it seems to
have gone away as a result of treatment. The one
cure that works without fail is the use of a UV
sterilizer. This kills the algae on a continuous
basis and can produce results in a matter of hours.
UV sterilizers are very safe and introduce no chemicals
to the water. They also have the added benefit of
killing free swimming parasites in the water.
As with any pond setup, you should be certain to
have a good filter with biomedia (such as Seachem's
Matrix or Matala Mat) in your pond filter to house the beneficial
bacteria that fight ammonia. Failure to have a
good filter in combination with the use of a UV filter
can result in a deadly ammonia spike because UV light
does not discriminate between good and bad bacteria.
All floating bacteria will be killed, but beneficial
bacteria prefer to live on surfaces, so be sure they
have a lot of places to hang out so they won't all be
nuked by your UV sterilizer.
Other methods to try to
treat for Green Water:
Green Clean Granular
This is a rapidly oxidizing
substance that immediately eliminates surface algae and
can do a pretty good number (temporarily) on green
water. It is safe for use around pets and children
because it breaks down into water and oxygen.
Since the green water critter comes in through tap
water, it won't be long before it will be back.
Some people choose to use algaecides
and do frequent water changes to reduce the excessive
nutrient levels. Be very careful using algaecides
because they can rob the water of oxygen. This can
be a real problem on a hot day when oxygen levels are
lowest.
Some people have reported results
from using Seachem's Pond Clarigen to help coagulate the
algae and remove it through the filter. While this approach, it is
possible
that the condition will return.
Always remember that you should
follow dosage directions when adding algaecides and
water clarifiers. You can kill your fish if you
overdose!
