GH-Test (total hardness)
For determining the total hardness (GH) in freshwater aquaria
The total hardness (GH) constitutes the amount of dissolved magnesium and calcium salts in the water. If the concentration of these salts is low, the water is referred to as soft water, if the concentration is high, the water is referred to as hard water. The reading is usually given in degrees of German hardness (°dH), whereby 1 °dH equates to 10 mg per litre of dissolved calcium oxide. The concentration of these salts in the water affects the organic functions of the fish and plants. Therefore, it should be tested on a regular basis.
The optimum total hardness value depends on the species of fish. Many African (e.g. aphyosemion) and South-east Asian species (e.g. trichogaster) cope with hard water easily. On the other hand, South American tetra, for example, need soft water to feel comfortable. A hardness level of 3-10 °dH is favourable in a freshwater aquarium.
The Tropic Marin® GH-Test makes it possible to quickly determine the total hardness of your aquarium water. This test kit will do approximately 100 tests (depending on test results) that are both fast and accurate.
• Measurement range: 1 – 20 °dH • Accuracy: 0.5/ 1 °dH • For determining the total hardness in freshwater aquaria • Sufficient for approximately 100 applications • Measured on the German hardness scale (°dH) • Conversion Table for other units in the instruction manual included
How to use:
1. Shake the dropper bottle before use! 2. Rinse out the glass cuvette with tap water and then several times with aquarium water. 3. Fill the glass cuvette with exactly 5 ml of aquarium water using the dosing syringe. 4. Now add the GH test reagent drop by drop (shake the cuvette after each drop), until the colour of the solution changes from PINK to TURQUOISE. 5. The number of drops indicates the total hardness of the solution in °dH, e.g. 8 drops = 8 °dH. To increase the accuracy of the measurement, a 10 ml water sample (instead of 5 ml) can be used. In that case, 1 drop corresponds to 0.5 °dH, i.e. 15 drops = 7.5 °dH. 6. Rinse out the glass cuvette and the syringe thoroughly with tap water after the measurement process.
How to correct unfavourable values
If the total hardness level is too high, we recommend exchanging a proportion of the water for soft water. Ask your specialist pet retailer for advice regarding this. If the total hardness level is too low, we recommend adding Tropic Marin® PRO-DISCUS MINERAL to increase the hardness.
Shelf life and storage6 months after opening. Store in a cool, dark place.
The entire instruction manual as PDF file can be found here: GH-Test
GH-Test 28230 Refill Pack 28774