Tropical TEST GH/KH General & Carbonate Hardness Test Kit

The Tropical TEST GH/KH is a titrimetric water testing kit designed to measure both general hardness (GH) and carbonate hardness (KH) in aquariums and ponds. It is aimed at fishkeepers who need accurate hardness readings to maintain stable, species-appropriate water conditions.

How It Works

Testing uses a titrimetric method — add the reagent solution drop by drop until a colour change occurs. Each drop of reagent corresponds directly to one German degree of hardness, so reading your result is straightforward: count the drops, get your value in °dGH or °dKH.

Why GH and KH Matter

General hardness reflects the concentration of dissolved calcium and magnesium ions, while carbonate hardness indicates the buffering capacity of your water. Many species tolerate a broad hardness range, but for those that do not — particularly species with specific breeding requirements — keeping GH and KH within the correct parameters is essential for long-term health. Carbonate hardness also plays a direct role in pH stability: higher KH buffers pH more effectively, but can make intentional pH adjustment more difficult when required.

What's Tested

• General hardness (GH) measured in °dGH
• Carbonate hardness (KH) measured in °dKH
• Suitable for use in aquariums and ponds

For a complete picture of water chemistry, the Tropical TEST GH/KH works alongside other tests in the Tropical range. Used consistently, it gives you the data needed to make informed decisions about water preparation and conditioning before issues have a chance to develop.