of Pond Water
As hardy as koi are, long term exposure to poor water quality will
cause stress and disease. Clear water is not an indication of good
water quality Therefore we need to test our pond water periodically
rather than wait for disease symptoms to appear.
to Test For
'A pond is basically a
toilet'. Fish waste must not be allowed to accumulate in a pond. At
the end of it all, this means a biological filter must be operating
properly Fish waste and other organic debris result in the first stage
of the nitrogen cycle, a series of events that produce some of the
compounds that we test for - ammonia, nitrite and nitrate. Besides
that pH value and dissolved oxygen are also important parameters to be
tested. Water hardness which indicates the amount of dissolved
minerals in the water needs to be tested too.
to Test ?
Spot tests are important
if the pond water indicates a toxic or adverse condition. For example,
high ammonia, where corrective action has to be taken immediately
Where as it is advisable to test our pond water on a regular basis
such as every week and table the results so that trends on direction
can be noted early By knowing the direction that the water quality is
taking, we can take corrective measure before the problem gets out of
hand. If there are major changes to the pond system, such as
installing a new filter, major pond cleaning or repair, daily testing
of pond water is encouraged to monitor the effect of the change.
Look for user friendly
type of test kit which is reliable and easy to use. It is very common
to get Home Kit that come with a small container for a measured sample
of pond water, a chemical to add to the water sample that will cause
the water to change colour. We can then refer to a standard colour
chart and compare the results. Most test kit come in either 'Master
Pack' which contain several basic test or single test pack. The basic
tests are usually ammonia, nitrite, nitrate and pH value.
Ammonia, introduced by
fish waste and decomposing organic debris, is the most toxic nitrogen
compound. It is present in two forms in the pond - free and ionized.
Free ammonia is the most toxic and will cause death in very low
concentrations. Problems associated with non - lethal elevated level
of ammonia include gill disease, dropsy and finrot. Test kit measure
the total ammonia (free plus ionized). With a properly functioning
biological filter, the ammonia level is usually zero in the pond and
should at least be under 0.1 ppm (mg/l). If the level of ammonia is
elevated, make partial water changes and stop feeding the fish until
the situation is corrected.
Nitrosomonas bacteria in
the filter oxidize ammonia into nitrite, which is less toxic than
ammonia, but still bad as it inhibits the ability of the blood to
carry oxygen. Our pond may experience a nitrite spike if Nitrobacter
colony is not sufficient to oxidize it to nitrate. If the level of
nitrite is elevated as shown in our test results, we should make
partial water change and if necessary add commercial bacteria high in
Nitrobacter to the filter.
Nitrate is the end
product of the nitrifying of the nitrogen cycle. It is mush less toxic
for koi than either ammonia or nitrite. Nitrate is absorbed as food
and fertilizer for algae and is then reduced into free nitrogen by
anaerobic bacteria. An oxygenated, clean pond will not have any
anaerobic bacteria present, so nitrate will accumulate in the pond. An
algaecide is often used to kill or control the algae of which the
growth is encouraged by the presence of the nitrate. Partial water
changes usually will flush out the accumulating nitrate.
pH indicates the ratio of
hydrogen ions to hydroxyl ions on a logarithmic scale from 1 (pure
acid) to 14 (pure alkaline). Pure water is 7.0, meaning that there is
equal balance of hydrogen ions and hydroxyl ions. Most tap water in
Malaysia is around 7.0. Koi do best in water of 7.2 to 8.0. Koi can
tolerate a wide range of pH, from 6.5 to 9.0. Even though koi can
tolerate extreme of pH there are diseases directly cause by stress.
Acidosis is a reaction of fish to acidic condition, in which the fish
act highly agitated, with a lot of jumping. Whereas, alkalosis, a
reaction to conditions that are too alkaline, will cause the gill and
fin to be destroyed. To control pH we can use "pH up" or
"pH down" chemical which is available in most fish shop. We
can certainly consult experienced koi member or koi dealer for
Dissolved oxygen is
usually only a warm weather concern like Malaysia as it is associated
with water temperature and algae. The larger the fish, the greater the
oxygen demand - low levels will stress and kill our biggest koi. Ponds
that have been safe for many years can become a danger as our fish
grow larger. Algae takes up oxygen at night, and an algae bloom can
cause suffocation in large fish and inhabit the oxidation process of
nitrifying bacteria. Dying algae and decaying organic material also
takes up oxygen. Testing for dissolved oxygen allow us to determine if
our pond has maximum amount of oxygen at specific water temperatures.
Splashing the water into small droplets with underwater jets and
compressed air installation is a good way of promoting oxygenation.
In conclusion, testing gives us information that we need to ensure the
best possible water condition for our fish. It only takes a few
minutes a week and is about the best investment you can make. My
advice is to contact experience koi member of fish shop for help
whenever you have a problem. Do not keep the problem to yourself.