Zoolek GH/KH Water Hardness Test

The Zoolek Aquatest GH-KH is a set of two drop tests for measuring the general (GH) and carbonate (KH) hardness of aquarium water. Results are given in degrees of German hardness (°d).

The test suits both freshwater and marine aquariums.

According to the product data, the accuracy is 0.5–2 °d, depending on the volume of the water sample taken as described in the instructions. The reagents are enough for approximately 2 × 300 °d.

Add the reagent to the water sample drop by drop and count every drop. Continue until the colour of the solution matches a shade on the colour scale, which marks the end of the reaction.

The set includes 2 bottles of reagent, a colour chart, a test tube, a syringe and directions for use.