When keeping freshwater fish and plants, the general hardness (GH) and carbonate hardness (KH) of aquarium water should match their natural habitat. The API GH & KH Test Kit helps you duplicate the natural habitat of your fish to prevent stress, keeping them healthy! The kit includes 2 bottles of liquid reagent, 2 glass test tubes with snap-tight caps, and step-by-step instructions. 

We recommend that you take a few minutes each week to monitor your aquarium conditions and create a better underwater world for your fish. Testing your aquarium water has never been so easy or accurate!

Package Description: 1 Kit

Serving Size: ..

Number of Servings: ..

Ingredients: Testing solution test tubes with caps computer analyzed laminated color card to read results.

Includes 2 test bottles, easy-to-ready instructions, and glass test tubes

1. Carbonate Hardness (KH):

• Read thoroughly before testing. Do not allow Test Solutions to get into aquarium.
• Remove childproof safety cap using one hand to push red tab while unscrewing cap with free hand.
• Rinse a clean test tube with water to be tested.
• Fill the test tube with 5 ml of aquarium water (to the line on the test tube).
• Add Carbonate Hardness Test Solution, one drop at a time. Hold dropper bottle upside down in a completely vertical position to ensure uniform drops. After first drop is added, solution will turn blue (If the water sample contains only 1°dKH, the solution will turn from clear to its yellow endpoint after the first drop is added).
• Cap the test tube and invert several times after each drop. Count the number of drops being added. Do not hold finger over open end of the tube, as this may affect the test results.
• The test is completed when the water in the test tube, after having been shaken, turns from blue to yellow. If you have difficulty discerning the color after the first drop of test solution is added, remove the cap from the test tube and while holding it over a white background, look down through the tube.
• The Carbonate Hardness value is determined by the number of drops of the reagent that must be added to turn the water in the test tube bright yellow. Each drop is equal to 1 °dKH or 17.9 ppm KH.

2. General Hardness (GH):

• Read thoroughly before testing. Do not allow Test Solutions to get into aquarium.
• Remove childproof safety cap using one hand to push red tab left while unscrewing cap with free hand.
• Rinse a clean test tube with water to be tested.
• Fill the test tube with 5 ml of aquarium water (to the line on the test tube).
• Add General Hardness Test Solution, one drop at a time. Hold dropper bottle upside down in a completely vertical position to ensure uniform drops. After first drop is added, solution will turn orange (If the water sample contains only 1°dGH, the solution will turn from clear to its green endpoint after the first drop is added).
• Cap the test tube and invert several times after each drop. Keep count of the drops being added. Do not hold finger over open end of the tube, as this may affect the test results.
• The test is completed when the water in the test tube, after having been shaken, turns from orange to green. If you have difficulty discerning the color after the first drop of test solution is added, remove the cap from the test tube and while holding it over a white background, look down through the tube.
• The number of drops of the reagent that must be added to turn the water in the test tube green determines the General Hardness value. Each drop is equal to 1 °dGH or 17.9 ppm GH.