Why do I need this Information
Most fish are fairly adaptable
or we would not be able to to keep them. However there
are certain species which are not so adaptable, especially
when breeding them is concerned, also there is optimum
water condition and quality for each species and while,
by virtue of their adaptability, they may survive in other
conditions, one will never see them in their best condition
and displaying their full colourful beauty.
is wrong with my tapwater ?
Nothing at all for the purpose
for which it is intended. The various water authorities
have a duty to produce water of a potable quality, this
means that it is suitable for humans to use, without any
additional treatments for the purpose of cooking and drinking.
lt does not mean it is perfect for fishkeeping indeed
as it is 'pure' and some of these chemicals
remain in the water it follows that freshly drawn tapwater
can in fact be harmful to your fish. A case in point involves
a gas named Chlorine. This gas is used in the purifying
process and a certain amount becomes dissolved in the
water. Fortunately it is a volatile gas and will escape
to the air if the water is drawn from the tap some 24
hours before use and allowed to stand in a container with
the surface exposed to the air. An excess of Chlorine
is quite capable of killing delicate tropical fish and
is unpleasant to the human palate as you have probably
discovered from time to time when drinking water freshly
drawn. The hardness/softness and acidity/alkalinity of
water from various localities differ considerably so the
serious fishkeeper must make the effort, quite considerable
at times to change the nature of the tap water to that
suitable for his or her fish.
What does hardness/softness
and acidity/alkalinity mean ?
These are terms used to describe
certain qualities of the water concerned. A simple explanation
is that hardness/softness relates to the amount of salt
which the water has acquired since leaving the cloud,
from which it originated, as rain. Hard water contains
a lot of these salts while soft water contains little.
Acidity/alkalinity of water refers to the ability to neutralise
alkali/acid. It should not be confused with the acid/alkaline
ph value shortly to be mentioned.
do I know what sort of water I have got ?
Fortunately it is easy to check
the quality of water by very simple tests. There are various
'test kits' on the market and although at first site they
appear expensive, when one considers that only a few drops
from them are required to carry out a test it follows
that each package can complete several tests, thus making
the cost per test reasonable. The normal procedure is
to take a small measured quality of water and to add to
this a specified number of drops from one or more solutions
in the test kit and then compare the resultant colour
of the water to the colour chart.
How do I measure hardness/softness
This can be measured in various
ways but generally accepted method relating to fishkeeping
is to use the German method of degrees, the higher number
of degrees the harder the water. The question of hardness
is complicated by the fact that the three types of hardness
are generally considered total hardness, carbonate or
temporary hardness and non-carbonate or permanent hardness.
What is Total Hardness
is self explanatory and refers to the total amount of
salts which are contained in the sample of water. The
salts which are of interest to us are bicarbonates, carbonates,
and sulphate's of calcium and magnesium.
What is Carbonate or Temporary
This is is a little confusing
in that it refers to the bicarbonates and small amounts
of carbonates (carbonates are not very soluble in water).
This type of hardness may be removed by boiling water
which converts the bicarbonate into virtual insoluble
carbonate which is precipitated. This is the explanation
for 'fur' found in kettles in hard water areas. For those
with soft knowledge of chemical symbols what happens is
as follows, CA (HCCO 3 ) 2 = (When boiled) Ca CO 3 + CO
2+ H2O. Calcium bicarbonate*, Calcium carbonate, Carbon
dioxide, Water (*Bicarbonate is know scientifically known
as Hydrogen carbonate) in other words the Calcium bicarbonate
is broken down into calcium carbonate (mostly deposited
on the inside of kettles or other vessel used), Carbon
dioxide (a gas which escapes into the air) Water.
What is Non carbonate or
permanant hardness ?
is found by subtracting the carbonate hardness from the
total hardness and is caused by the amount of calcium
and magnesium present in the water, normally in the form
of sulphate's, nitrates and chlorides. This type of hardness
can not be remove by boiling as in the case of carbonate
hardness. There are two main methods of removing this
type of hardness, first by boiling away the water in a
closed vessel the steam being conducted to a condenser
where it is cooled, usually by a water jacket and thus
condensed back in to water which is soft having left the
salts behind. This method is expensive in operation but
does produce virtually pure water, in fact this water
is so pure that it would not support fish life as certain
'trace elements' which they need have been removed. The
second method is by ion exchange,as used to produce distilled
water for car batteries. This method uses an ion exchange
resin, often sodium zeolite,which will exchange its sodium
for the calcium in the water. The terms used in respect
of hardness using the German system are :- 0 GH= General
hardness (permanent) :- 0 KH= Carbonate hardness (temporary).
What are the the other
methods of reducing water hardness ?
Go to our article section for
more information on reducing water
What is pH. ?
The pH value indicates whether
a liquid reacts in an acidic, neutral or basic (alkaline)
manner. The pH scale ranges from 0 (very acidic) to 14
(very basic), with neutral at about 7. The pH value shows
the concentration of certain ions which are responsible
for an alkaline or acidic reaction. Most freshwater fish
and plants can only survive in the pH range of 6-8. Some
specialist species require ranges of 5 or 9. Maintaining
a pH level of around 7, in the neutral area is recommended
for the following reasons.
As a one point fluctuation in the
pH value corresponds to a tenfold alteration in the ions
responsible for the change, any change in the pH value
is stressful for all the organisms in the water, whether
fish, plants or micro-organisms. Sudden deviations in
pH levels may lead to increased susceptibility to disease
in fish, poor growth in plants and may even kill micro-organisms.
JBL Biotope aquarium water. JBL. GmbH & Co.KG, D-67141
Neuhofen/Plaiz, Germany. 33p.
This article first appeared in
the Greenock & District Aquarist Society newsletter
"The Angelfish" October 1995. no 4. and is also
duplicated on the Help index on Water