JBL KH Test
Carbonate hardness test
Recommended level in freshwater: 4 - 8? dKH (GKH)
1 drop = 1? dKH (GKH).
Colour change from blue to yellow.
For fresh- and saltwater.
For further details on the significance of hardness in the biological system of your aquarium, see the JBL brochure entitled "Was - Wie - Warum?" (What - How - Why?), No. 2.
Our tip for ecologically-minded "aquarians": All reagents for the JBL Test Sets are also available as reasonably priced refills.
The JBL Test Sets range comprises: TH, pH 4,5 - 9, pH Special, CO2, ammonium, nitrite, nitrate, iron, phosphate, calcium.
Repeatedly rinse the test cup with the water to be teste
Fill test cup with the water to be tested up to the 5 ml-marking (CAUTION: the lower line of the water level must coincide with the marking).
Add the reagent drop by drop: counting the drops: until the colour changes from blue to yellow-orange.
One drop of reagent solution used corresponds to 1? carbonate hardness (German scale). See table below for conversion into other commonly accepted units of measure.
alkaline earth ions mmol/l
alkaline earth ions mval/l
German degree ?d
English degree ?e
Frensh degree ?f
1 mmol/l alkaline earth ions 1,00
1 mval/l alkaline earth ions 0,50
1 German degree 0,18
1 ppm CaCO3 0,01
1 English degree 0,14
1 French degree 0,10
Depending on origin and consistency of the subsoil, water may contain varying quantities fo alkaline earth salts. Owing to the effects of CO2, a large proportion of these salts is represented by carbonates. By definition, the proportion of calcium and magnesium salts represented as carbonate is described as carbonate hardness. As a rule, the carbonate hardness is below the total hardness value. In certain exceptional cases (e.g. many tropical waters) the carbonate hardness can be higher than the total hardness. Fish and plants thrive well at a carbonate hardness of roughly between 3 and 15?d. For successful CO2 fertilization, the carbonate hardness should not fall below 4 to 5?d. For optimized pH buffering action in saltwater, a carbonate hardness around 10-15?d ought to be maintained.
What to do in the event of unfavourable values:
There are variousmethods for reducing water hardness. Ask your pet shop specialist for details. Use JBL Aquakal or JBL AquaDur plus for increasing the carbonate hardness in freshwater. Use JBL CalciuMarin in saltwater.
The JBL KH Test Set is an easy to use quick-test for determining the carbonate hardness or the antacid capacity of saltwater and freshwater.
(Recommended level in freshwater: 4 - 8? dKH (GCH))Product description
The carbonate hardness
The carbonate hardness CH is one of the most important water parameters in aquarium keeping and for garden ponds. The CH stabilises the pH-level and therefore prevents any dreaded plunge or sudden steep rise in pH levels, both of which are equally dangerous.
In normal community aquariums and ponds, the CH should never drop below 4? GCH. Even if the initial water contained sufficient CH levels, the CH in the aquarium and pond may decrease. This may be the result of vigorous bacterial activity or a lack of CO2 - with plants and algae extracting the CO2 they require from the CH. Consequently the CH decreases and the pH-level is unstable.
The CH in the freshwater aquarium can be increased by:
The addition of JBL AquaDur plus (increases TH and CH)
The addition of JBL AquaDur Malawi/Tanganyika (increases CH higher than TH)
The CH in the garden pond can be increased by:
The addition of JBL Alkalon Combi (increases TH and CH)
The CH in the saltwater aquarium can be increased by:
The addition of JBL CalciuMarin (increases CH, calcium and strontium)
The CH in the freshwater aquarium can be reduced by:
Filtering through JBL Tormec (black turf granulate) (only minor reduction possible)
The addition of JBL Aquacid pH-reducer (careful: in small steps!!!)
The use of reverse osmosis equipment (JBL Osmose 120) (removes CH and TH)
available in the following sizes:
2536000 JBL KH Test-Set
2536100 JBL KH Reagens