NT Labs Hardness Test

NT Labs Hardness Test

The NT Labs Hardness Test is a vital tool for monitoring KH and GH readings in an aquarium. Carbonate Hardness (KH) is a measure of the buffering capacity of the water in your aquarium to pH changes. General Hardness (GH) is a measure of the total amount of minerals dissolved in the water. Soft water is low in dissolved minerals, while hard water is rich in minerals, and high hardness may be responsible for limescale build-up.

Using the NT Labs Hardness Test, you can easily monitor both KH and GH levels and fix them before they become a problem. This test kit measures KH in dKH (where one dKH = 17.8 ppm as CaCO3). It is essential to maintain a minimum KH level of at least 4 dKH at all times. The correct GH depends on the type of fish being kept. For soft water species, aim for a GH of around 3 to 6 dGH, while for hard water species, 10 to 15 dGH is the correct range.

Ensure the test tube is clean, and after collecting a 5 ml water sample in the clean test tube, take the KH reagent and add one drop, mix and the water sample should turn pale blue. Keep adding drops, one by one (remember to count the drops), mixing between drops, until the blue colour turns to yellow. The number of drops, including the first drop, needed to bring about the colour change is equal to the KH value in dKH. Should the first drop of reagent turn the sample yellow then the KH value is below 1 dKH – this is extremely dangerous for fish.

This product contains up to 80 water tests.

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McMerwe’s comments: We recommend the NT Labs Hardness Test to maintain the right mineral levels for your aquarium water, and ensure there is a buffer present in case of pH spikes. It’s simple to use and gives quick, accurate results—perfect for monitoring water quality in your aquarium. A great tool for both planted and fish-only setups. [Rating: 5/5]