For determining the alkalinity (KH)
The carbonate hardness (KH) or alkalinity of a water sample characterises the buffering capacity, i.e. the ability to maintain the pH value of the water. There are many terms in water chemistry to describe the buffering capacity with varying definitions. The term “carbonate hardness” is customary in fishkeeping; however, it is the alkalinity which is measured. In this test, both terms are used synonymously. The reading for alkalinity is usually given in degrees of German hardness (°dH).
The alkalinity should be tested in all aquariums with great regularity. If the alkalinity in the aquarium is too low, the pH value can sink (sudden drop in acidity) to a level which is life-threatening for many fish and invertebrates. In reef aquariums, an adequate alkalinity level is essential for strong coral growth. On the other hand, an overly high alkalinity in saltwater tanks can lead to calcium carbonate precipitates and also have a negative impact on coral growth. The alkalinity in saltwater aquariums should range from 6 to 9 °dH. The alkalinity in freshwater aquariums should not fall below 3 °dH.
The Tropic Marin® KH-Test kit makes it possible to quickly determine the alkalinity of your aquarium water by ease of use and high accuracy.
• Measurement range: 1 – 20 °dH • Accuracy: 0.5/ 1 °dH • For determining the alkalinity in 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 KH test reagent drop by drop (shake the cuvette after each drop), until the colour of the solution changes from TURQUOISE to PINK. 5. The number of drops indicates the alkalinity 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
To increase the alkalinity when levels are too low, we recommend using Tropic Marin® TRIPLE BUFFER or LIQUID BUFFER for saltwater applications and Tropic Marin® RE-MINERAL TROPIC for freshwater applications. If the alkalinity level is too high in your saltwater aquarium, we recommend using Tropic Marin® ALCA-BALANCE.
Shelf life and storage6 months after opening. Store in a cool, dark place.
The entire instruction manual as PDF file can be found here: KH/Alkalinity-Test
KH-Test 28240 Refill Pack 28776