Maintain a healthy and stable aquatic environment with the NT Labs Hardness Test Kit, designed to measure both KH (carbonate hardness) and GH (general hardness) in your pond or aquarium. Understanding your water hardness is essential for the wellbeing of your fish, plants, and pond ecosystem.

What is KH?
KH, or carbonate hardness, measures the buffering capacity of your water. A stable KH level prevents sudden pH fluctuations, helping create a more balanced environment for aquatic life. For ponds, an ideal KH is 6–8 dKH, with a minimum of 4 dKH. Low KH levels can be adjusted using a buffer to maintain long-term water stability.

What is GH?
GH, or general hardness, indicates the mineral content in your water. Hard water contains more minerals, which can affect everything from pond filters to aquarium equipment. GH levels are measured in dGH and ideally range from 8–12 dGH for most ponds. Aquarium requirements vary depending on the species: South American cichlids like Kribs and Rams prefer softer water, while African cichlids such as Malawis need harder water.

Features & Benefits:

Measures both KH (carbonate hardness) and GH (general hardness)
Simple liquid drop testing with clear results
Includes up to 80 tests, complete with test tubes and reagents
Suitable for freshwater aquariums, tropical and coldwater fish, and garden ponds
Helps stabilize pH, protect equipment, and promote healthy aquatic life

Take the guesswork out of water quality management and ensure your pond or aquarium remains clear, balanced, and thriving with the NT Labs Hardness Test Kit.

Freshwater Test Kits

API Ammonia Test Kit (Salicylate)

API Freshwater/Saltwater Nitrate Test Kit

API Freshwater Mini pH Kit

TMC Salifert Copper ProfiTest Kit

Tetra Test General Hardness - Aquarium Water testing Kit

Seachem MultiTest: Iron 75 Tests (968)

Seachem MultiTest: Ammonia 75 Tests (950)

NT Aquarium Starter Kit

Interpet Complete Dip Test Kit

API 5 In 1 Test Strip 100 Strips

API Ammonia Test Strip X 100

NT Labs Hardness Test Kit