Many new
fishkeepers shy away from the subject of water quality and water testing. Terms
such as ppm, ammonia, nitrites, nitrates, hardness, pH, GH, KH, dGH, and the
fact that all of these are interconnected seems like a whole laboratory and a
degree in chemistry may be required. The subject of water quality and testing
can be as simple or as complex as desired. For most aquariums, water quality and
water testing is far simpler to understand and carry out than it first seems.
All these water quality factors affect the health and vitality of your fish, and
all are also invisible to the eye in the aquarium. For this reason, crystal
clear water should never be taken as proof of a healthy aquarium. Incorrect
water quality is the prime suspect in virtually all algae and fish health
related problems and regular water testing is the easiest way to prevent any
disheartening and potentially expensive downfalls. There are a number of methods
of water testing but first it is vital to understand what you are testing and
why.
Ammonia (NH3)
The food that enters your aquarium is the source of virtually all waste in the
aquarium. As the fish digest food, they inevitably produce waste matter, a large
proportion of which is ammonia. Ammonia, even at low levels is toxic to fishes
and other forms of aquatic (and terrestrial) life. Thankfully, the prime
function of the filter in your aquarium is to house bacteria, which convert
ammonia into nitrites. A suitable established filter should continually convert
ammonia so that the quantity left in the water is well into safe levels. It is
important to test regularly for ammonia in both new and established aquaria. In
new aquariums, the filter will not be fully established and if the amount of
waste entering the aquarium exceeds the capability of the filter, ammonia levels
will rise. In an established aquarium, an un-noticed death or damage to the
filter by power cuts or incorrect cleaning will also cause rises in ammonia. A
sudden, un-noticed rise of ammonia can cause a significant number of deaths,
occasionally wiping out an entire aquarium.
Ideally, ammonia levels should be below 0.1ppm (ppm = parts per million) at all
times. It is likely that slight fluctuations will occur in new aquariums, as
long as the level is not above 1ppm for more than a few days, the first hardy
fish in the aquarium should be able to cope. If ammonia levels do rise, an
immediate 10-20% water change should be carried out, ideally at the same time as
a gravel clean, and feeding should be stopped for a few days. This will dilute
the ammonia content and reduce any near-future increases. Some chemical
additives or specialised filter media are designed to remove ammonia quickly and
are well worth using to quickly reduce ammonia related problems.
Nitrite (NO2)
Once the bacteria in the filter has converted ammonia, it produces nitrites,
which are still highly toxic to fishes but less toxic than ammonia. Because
nitrites come from the same source as ammonia, the same causes can be identified
for increases of nitrite. A new aquarium with an un-matured filter, too much
feeding, lack of gravel cleaning or a breakdown of the filter by power cuts or
incorrect maintenance may all cause increases of nitrites. Nitrite levels should
also be at around zero but some hardy fish will cope with extended periods of up
to a week or more with nitrite levels approaching 4ppm. The sensitivity of
fishes to nitrites depends largely on the species of fish but in all cases,
exposure to unsuitable nitrites will cause damage. The remedy for high nitrites
is also the same as for ammonia, an immediate water change and gravel clean
along with a reduction in the feeding should quickly reduce nitrites. Again,
additives are also available to quickly absorb and remove nitrites.
Nitrates (NO3)
The final process of the bacteria in the filter is to convert nitrites into
nitrates. Nitrates are far less damaging than either ammonia or nitrite and only
become toxic at high levels. Rising nitrates however, can reduce a fish's
immunity to disease over long periods of time. If the aquariums nitrate levels
do become high, the existing fish may seem healthy but any new fish may succumb
to disease quickly, and also pass diseases to the existing fish. Most hardy
tropical freshwater fish will live healthy at nitrate levels as high as
50-100ppm, In some cases, hardy fish can survive for years at levels above
250ppm, although they will never be at full health and vitality. To keep a
healthy aquarium, nitrates should be kept below 50ppm. This can sometimes be
tricky as some tapwater sources may contain nitrate levels this high. In cases
where tapwater levels are high, the addition of live plants and / or nitrate
absorbing filter media to the aquarium should effectively keep nitrates low. In
cases of high nitrates, a series of small water changes should quickly reduce
levels. Regular water changes will continually keep levels low. If they do not,
it is likely that either your tapwater contains high nitrate levels or the fish
are being continually fed too much food.
pH
For many new fishkeepers, pH is a subject that can be avoided without too many
problems as long as they trust the advice of a good retailer without question.
pH however, has a large effect on the health of fishes. This is because
different fish prefer different pH levels, and also that pH levels vary in
tapwater depending on which area of the country you live in. As a very basic
description, pH is a measure of how acidic or alkaline the water is and depends
on the ratio of hydrogen ions in the water. It is not too important to
understand exactly how pH works, but suffice to say that water with a pH below 7
is acidic and water with a pH above 7 is alkaline, pH 7 is considered as
neutral. The ideal pH level for most tropical fish normally lies somewhere
between pH 6 and 8 and depends on where they originate in nature. Fishes from
alkaline waters, such as the rift lake cichlids of Africa, prefer water with a
high (alkaline) pH of around 8-8.5. In contrast, many tetras which come from
acidic waters such as those of heavily vegetated streams and rivers in the
Amazon basin, prefer a low (acidic) pH of around 6-6.5. Apart from issues of
compatibility, these two groups of fish would be difficult to provide ideal
conditions for in the same aquarium. The majority of aquarium fish will live
happily in water with a pH between 6.5-7.5. It is only when the water in your
aquarium falls outside of this range that you may be forced to either alter the
water or stock only the fish which suit your pH level.
pH changes
Whatever the pH level of your aquarium, it is vital that it remains stable and
never changes drastically over a short period of time. Sudden changes can occur
in aquariums with little water hardness (see water hardness below) or when an
incorrect source of water is used, such as pure rainwater. Over time, pH will
naturally slowly drop in an aquarium because the wastes produced by fishes and
wood are acidic. The effect of long term drops and the risk of sudden changes
can be prevented simply by carrying out regular water changes. Water changes
will continually replace the minerals that 'buffer' the pH level and prevent
changes.
Altering pH levels
It may be required to alter the pH of your aquarium water or water source to
accommodate the needs of the fish you wish to keep. There are a number of ways
to do this and seeking advice from a good retailer is well recommended. Changing
acidic (low pH) water into alkaline (high pH) water is relatively easy as it
involves the addition of mineral substances. Calcareous (calcium containing)
rocks and substrates can be used for this purpose, as can specially made
chemical additives. Changing alkaline water into acidic water is a little
trickier as it involves the removal of substances. 'Natural' methods include the
use of bogwood or peat based filter media which both release acidic compounds
causing the removal of alkaline substances. Chemical treatments and additives
can also be used to lower pH but these should be used with great care and good
advice, incorrect use can result in unwanted and difficult side effects.
Hardness
Water can be termed as hard or soft depending on the amount of minerals and
salts it contains. Water with few minerals is considered soft, whilst water with
a high quantity is considered hard. Water hardness is closely linked to pH. Hard
water with many minerals has the ability to 'absorb' acidic substances and so
prevents drops in pH. This is why hard water often has a high (alkaline) pH
whilst soft water often has a low (acidic) pH. As with pH levels, different fish
prefer different hardness levels. In most cases, for new fishkeepers, hardness
is relatively unimportant and as long as regular water changes are carried out,
the aquarium should maintain a suitable hardness level. It is worth noting
though, that water with very little hardness may be prone to pH fluctuations,
which can be damaging to fish. Water with very high hardness prevents pH
fluctuations but also makes conditions difficult for aquarium plants, which may
not be able to absorb nutrients easily in hard water. It is worth testing for
hardness simply to monitor gradual rises or falls, in case of potential problems
caused by high or low extremes.
