Evalive Aquarium in Frankston has the best and biggest range of fish available. We serve Melbourne,Cranbourne and the Mornington Peninsula. Cichlids, Aquariums, heaters accessories plants tropical natives Here we discuss general hardness
Evalife Aquarium Melbourne's best aquarium
Products
Water quality
FILTRATION
about us
contact

gH

GENERAL HARDNESS (G.H.)

General hardness is the total concentration of calcium and magnesium compounds dissolved in water. Natural waters vary greatly in hardness, with extremes ranging from the very hard water of the Rift Lakes in Africa, to the very soft waters of the Amazon and its tributaries. Fish populations living in these waters have evolved to adapt to these specific water conditions. Measuring the water hardness is essential for successful keeping and breeding of aquarium fish. General hardness is measured in parts per million, (ppm) of dissolved calcium and magnesium. European aquarists measure hardness in German degrees of hardness (DH). One DH equals 18ppm. Water supplies vary greatly in hardness, and it is essential that the usual hardness of your tap water is known. For example, Melbourne tap water is very soft, between 20 - 40 ppm. Adelaide tap water is usually more than 200 ppm. The normal recommended hardness for a community tank is approximately 150 ppm. The general hardness of the rift lakes (Africa) is about 300ppm

 Hardness testing kits are easy to use and reasonably priced.


HARDNESS AND CONFUSING NAMES

It's unfortunate the term hardness has been used in many ways in aquarium literature. "General hardness" (GH), as described above, is basically the measurement of dissolved calcium and magnesium. "Temporary hardness" is that part of general hardness caused by carbon dioxide in water (carbonic acid) dissolving calcium. It is termed temporary because it can be removed by boiling. This is the cause of scale, in kettles and boilers, in hard water areas. "Carbonate hardness" is completely different, this is a measurement of carbonate and bicarbonate and controls pH or alkaline reserve (the buffering capacity of water).


HARDNESS OF THE COMMUNITY TANK

Calcium bearing materials should not be used in aquariums, unless for marines, brackish water or African (Rift Lake) cichlid tanks. Sandstone, marble, coral, seashells, beach sand and shell grit, all leach calcium into fresh water. The resulting increase in general hardness and pH levels are unacceptable. The hardness of aquarium water should be checked regularly, especially if the fish are looking sick.


TO HARDEN WATER

Very soft water needs to be hardened before it is used for most types of fish, and in particular livebearers, African (Rift Lake) cichlids, and brackish water fish, The simplest way to do this, is by



GENERAL HARDNESS

TO SOFTEN WATER

In the major cities in Australia the most simple way is to change some water.

The town water is usually fairly soft. (Except in Adelaide perhaps)

One could cart soft water from another town, collect rainwater, or buy distilled water. These methods may not be practical for large volumes. Rainwater from industrial areas and large cities is often badly contaminated. Distilled water often contains toxic levels of copper, so make sure water was distilled over glass, not copper.


To otherwise soften tap water is more difficult. The most practical method to soften water, is by use of ion exchange resins. These tiny brown beads of resin absorb calcium and magnesium ions in exchange for chloride ions. Aquarium water softening kits use this method, however, for treating large volumes of water, a commercial water softening unit should be installed.


PEAT MOSS

Good quality German peat moss can be used in filters to soften water, lower pH, and add humus and tannic acids. Change the peat moss every few weeks to ensure it does not decompose and re-release everything it has absorbed.



CALCIUM IN THE AQUARIUM

Aquarium water will progressively become harder if calcium bearing materials, as previously described, are used in the aquarium. In this case, simply remove the offending material and carry out a series of water changes with softer water, until the desired hardness is reached.


INCORRECT USE OF WATER CONDITIONERS

Aquarists sometimes add water conditioner to their aquarium every time they top up the tank after water has evaporated. Only pure water evaporates, leaving all mineral salts behind. If this practice is carried on long enough the water becomes so "thick", that all fish and plants will die. A TDS (total dissolved solids) tester or conductivity meters are available for detecting potential problems of this sort.


USE OF NEUTRALIZER BLOCKS

Aquarium neutralizer blocks, and holiday feeder blocks contain calcium and will harden aquarium water. Partial water change should be carried out every time one of these items has completely dissolved.


CHART OF GENERAL HARDNESS, TOTAL DISSOLVED SOLIDS & CONDUCTIVITY REQUIREMENTS OF

FRESHWATER FISH

       GENERAL HARDNESS                                                           TDS/CONDUCTIVITY

           REQUIREMENTS                                                                    REQUIREMENTS

0ppm

 

 

0ppm

0µs

20ppm

 

 

40ppm

75 µs

50ppm

 

 

100ppm

190µs

80ppm

NEONS & CARDINALS

 

160ppm

300µs

100pm

CORYDORAS CATFISH ANGEL FISH

MOST KILLIFISH PENCIL FISH

DWARF STH. AMERICAN CICHLIDS

MOST STH AMERICAN TETRAS PICTUS CATS DISCUS

MOST AUST & N.G. RAINBOWS

200ppm

380µs

150ppm

DANIO GOLDFISH ELEPHANT NOSE MOST BARBS MOST AFRICAN TETRAS

MOST CENTRAL & SOUTH AMERICAN CICHLIDS

CELEBES RAINBOW MOST SHARKS SIAMESE FIGHTERS MOST RASBORAS

300ppm

570µs

200ppm

HALF BEAKS KUHLII LOACH

MOST GOURAMIS GLASS CATFISH

400ppm

755µs

250ppm

 

 

500ppm

940µs

300ppm

GUPPIES MOLLIES PLATTIES SWORDTAILS GLASS FISH

BUMBLEBEE GOBIES BLIND CAVE FISH SOME AUST. NATIVES AFRICAN RIFT LAKE CICHLIDS

600ppm

1130µs

350ppm

 

 

700ppm

1320µs

400ppm

 

 

800ppm

1500µs

450ppm

SCATS MONOS

ARCHER FISH

900ppm

1700µs

500ppm

 

 

1000ppm

1880µs