4
5
water or reserve osmosis water.
What action shall I take if...
...the carbonate hardness is too high?
Add
Tetra pH/KH Minus
to obtain the carbonate
hardness you require for your aquarium water.
To achieve constant water parameters, check
the carbonate hardness every week.
...the carbonate hardness is too low?
Use
Tetra pH/KH Plus
to increase the bicarbonate
content in the aquarium water and to buffer the
pH value on a longer-term basis. We recommend
that you check the carbonate hardness weekly
after adding the water care product.
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The pH value
Chemically pure water has a pH value of 7, and is
called neutral. When water is neutral, there is an
equal amount of acids and alkalines. As more acids
are added, the pH value falls below 7; whereas more
alkalines cause it to rise above 7. The pH value is a
logarithmic scale, i.e. if the pH value changes from
6.5 to 7.5, it represents a 10-fold change in acidity.
A sudden drop in the pH value (acid collapse) can
occur in water with a carbonate hardness below
3° dH. pH values between 6.5 and 8.5 are suitable
for virtually all fish in freshwater aquariums. Fish
from black-water rivers prefer soft water with pH
values ranging from 6.0 to 7.5. East African cichlids
like hard water with pH values between 7.5 and 8.5.
Since all fish, plants and micro-organisms react
very sensitively to extreme changes to the pH
value, it should be tested at least once a week.
The test procedure
Please read this section carefully before
starting the test. The test measures pH values
ranging from 5.0 to 10.0. The illustrations
below should simplify the procedure.
1. Rinse the test vial with the sample water.
2. Fill the test vial up to the 5 ml mark with sample
water.
3. Hold the bottle with the test reagent upside
down and add 7 drops to the test vial.
4. Shake the test vial gently.
5. Hold the test vial against the colour chart and
match the shade of the test solution to the colour it
comes closest to on the colour chart. Read the value.
After each test, rinse the vial thoroughly with
tap water.
What action shall I take if...
...the pH value is too high?
Add
Tetra pH/KH Minus
to achieve the pH value
you require for your aquarium water. Add
Tetra
ToruMin
to supply peat extracts and humic acid
to create black water conditions. Use
Tetra CO
2
Optimaten
to regulate the pH value by adding carbon
dioxide, part of which dissolves into carbonic acid
in the aquarium water and causes the pH to fall.
These measures are taken to avoid
drastic changes to the pH level.
...the pH value is too low?
Use
Tetra pH/KH Plus
to increase the bicarbonate
content in the aquarium water and to buffer the pH
value on a longer-term basis. In general, the higher
the bicarbonate content, the higher the pH value.
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Ammonium/ammonia (NH
3
/NH
4
+
)
The first stage in the degradation process for organic
nitrogenous substances, such as fish excreta, food
and plant remains, leads to the formation of ammonia
(NH3), toxic to fish, and ammonium (NH4+), which is
harmless. Both forms (ammonium/ammonia) can be
brought into equilibrium via the pH value. As a rule, a
high pH value (>8.5) represents more toxic ammonia;
a low pH value (<7.5) signifies more harmless
ammonium. To make sure your fish are not at risk,
check that the pH value is within the acceptable
range. Also, keep the ammonia concentration as low
as possible. In a biologically intact aquarium, the
concentration of ammonia is so low that it is virtually
undetectable.
Organic
substances
Food remains
Plant remains
Fish excreta,
fish urine
Oxygen
Ammonium
NH4
Ammonia
NH3
Heavy metals
NitriteNO2
Nitrate
NO3
Degradation by
bioactive filter
Within limits,
effective as a plant
fertiliser
Keep out of the reach of children. If swallowed,
seek medical advice immediately and show this
container or label.
GH: Highly flammable. May cause sensitization by
inhalation and skin contact. Do not breathe fumes.
Avoid contact with skin. Contains piperazine.
KH: Flammable.
Highly
flammable
Harmful
Flammable. Irritating to eyes. Vapours may cause drowsiness and
dizziness. Keep out of the reach of children. If swallowed, seek
medical advice immediately and show this container or label.
Irritant
The water hardness influences the organic functions
of creatures in the water to a significant extent.
A distinction is made between the total (general)
hardness, characterised by alkaline earth salts,
and the carbonate hardness, which acts as a
buffer to the pH value. The quantities of calcium
and magnesium salts are used to measure the total
hardness. A high proportion creates hard water; a
low proportion leads to soft water. Values between 6
and 16° dH (= German degree of hardness) are ideal
for keeping most ornamental fish.
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Carbonate hardness (KH)
In addition to calcium and magnesium salts,
nearly all bodies of water also contain other salt
components, such as bicarbonate. The carbonate
hardness and the pH value are closely linked.
Bicarbonate, which is important for the aquarium,
acts as a buffer, and prevents the pH value from
changing too drastically and suddenly. A KH value
between 3° dH and 10° dH is recommended.
The test procedure (GH and KH)
Please read this section carefully before
starting the test. The illustrations above
should simplify the procedure.
1. Rinse the test vial with the sample water.
2. Fill the test vial up to the 5 ml mark with
sample water. Accuracy is enhanced if the
test is carried out using 10 ml aquarium water.
3. Hold the bottle with the test reagent upside down
and add liquid, drop by drop, to the test vial.
4. Shake the vial gently after each drop
and count the number of drops required to
change the colour of the water sample.
5. With the
GH
the colour changes from
red
to
green
. With
KH
the colour changes from
blue
to
yellow
. If the colour changes after
just one drop, the value is 0 – 1° dH.
6. The number of drops required to make the liquid
change colour represents the degree of hardness.
For example, 3 drops = 3° dH. If the vial contains
10 ml aquarium water, 1 drop of the test fluid
= ½° dH.
After each test, rinse the vial thoroughly with
tap water.
What action shall I take if...
...the total hardness is too high?
The total hardness can be lowered by
adding soft water, e.g. rainwater, distilled
UK
1. Why test the aquarium water?
Water is characterised by its environment and
differs all over the world, due to many different
influences. Pure rain water absorbs pollutants in
the atmosphere. When it seeps into the ground
and becomes ground water it changes its chemical
composition again. In addition, substances that are
harmful to fish, such as chlorine and copper, may
also be found in tap water. The quality of the water
in the aquarium also changes due to biological
and chemical processes. Although nowadays
most popular aquarium fish are bred in captivity,
they originate from the tropics or subtropics. To
give your fish the best possible environment, we
recommend that the water parameters are tested
regularly once a week. In special situations,
such as when setting up an aquarium or adding
new fish, they should even be tested daily.
2. Tips for long-term
good water quality
There is no single way for creating ideal aquarium
water – and there never will be because no two
aquariums are alike. Every single aquarium is a
unique habitat. For this reason, we suggest you seek
advice from your specialist dealer on which water
parameters are suitable for your fish and plants.
However, this general advice should be
followed:
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Avoid stocking the aquarium with too
many fish!
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Do not overfeed your fish!
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Make sure you have a properly
functioning filter!
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Regularly carry out partial water
changes and remove plant and
food remains from the bottom of the
aquarium!
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Ensure healthy and dense plant growth
3. The water values and
the test procedure
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General hardness (GH)
