API KH Carbonate Hardness Fresh & Salt Water Aquarium Test Kit

Rated 5 out of 5 stars
$15.98 Chewy Price
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About This Item


  • Tests tap, fresh and saltwater for carbonate hardiness (KH)
  • Low KH levels can cause rapid and wide shifts in pH levels which can stress fish and cause illness or death
  • Comes with test tube, test drops and color chart
  • Test regularly to maintain healthy tank
  • Easy-to-follow instructions, simply compare results with the color chart and follow the recommendations if action is needed.

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About API Testing

Testing the Waters

For fish to thrive, their aquarium water must be similar to the water in their natural environment. Poor water quality can cause stress, illness and even the loss of your fish. Important water quality parameters include ammonia, nitrite, nitrate, and pH. These can vary over time, and they are invisible to the eye, which is why it is necessary to test weekly. Choose from a wide range of API testing options like the Freshwater Master Test Kit or 5-in-1 Test Strips to accurately evaluate your water.

Pressed for Time? Just Dip and Read

Simply dip an API test strip into your aquarium, swirl it twice, and then use the color-coded chart to determine if your water is within safe parameters or if adjustments are needed. That’s it! API test strips are available in a 5-in-1 version, which includes testing for pH, nitrite, nitrate, carbonate, and general hardness. Ammonia and pH test strips are also available so you can mix and match according to your needs.

The Scientific Approach

Get professional results from the comfort of your home with API test kits. Measure up to six parameters with API Master Test Kits, or pick and choose from a wide variety of individual test kits. Both types of kits come with test tubes and a laminated, calibrated color card. API test kits allow for numerous tests, making them an inexpensive way to help keep your aquarium water quality in check.

How to Correct Aquarium Water Parameters

Too Much Ammonia?

Ammonia is released into the water through gills, urine, uneaten food and more. API Ammo-Lock detoxifies it instantly.

Inappropriate pH Levels?

Fish require a specific pH level to thrive. Use API pH Down to lower freshwater aquarium water pH to the right level.

Too Much Nitrite?

Use API Quick Start to quickly consume nitrite and help maintain an active biological filter.

Nitrates Too High?

API Nitra-Zorb helps remove nitrate and other toxins that can be harmful to fish and lead to algae growth.

About API

The team at API has a passion for fish and understands the rewards and relaxation fishkeeping can bring. For almost 60 years, they have developed premium products with a focus on proven and effective results. API offers a range of testing kits, water conditioners and nutritionally superior fish foods. They are dedicated to making a better underwater world for the benefit of fish and those who keep them.

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Fish TypeBetta, Bottom Feeder, Cichlid...Betta, Bottom Feeder, Cichlid...Betta, Bottom Feeder, Cichlid, Goldfish, Tropical FreshwaterBetta, Bottom Feeder, Cichlid, Goldfish, Tropical FreshwaterCichlid, Discus, Goldfish...
Aquarium TypeSaltwater, FreshwaterSaltwater, FreshwaterFreshwaterFreshwaterSaltwater

Questions & Answers

1 Customer Questions

How many drops for a fresh water test?
Answer by ChewyMar 04, 2020
This Aquarium Test Kit tests for carbonate hardness and general hardness in the water. To test the hardness of your water, you will need a clean test tube with 5 milliliters of water and adding 1 drop of this solution at a time. The instructions included in this kit will instruct on how to use based on your requirements.

ReviewsWrite a Review

Rated 5 out of 5 stars
2 Ratings
Would recommend to a friend

2 Customer Reviews

Rated 5 out of 5 stars
By Bryan on Nov 30, 2023

API KH test Kit

Seems to work well and easy to use but do not have anything to check the results of it against. So, it could be accurate or not.

Rated 5 out of 5 stars
By CoffeeLover on Apr 3, 2023

have used this weekly

Everyone who has a freshwater live planted tank should be testing carbonate hardness (kH) and general hardness (gH) at least weekly so make sure to add kH and gH test kits as part of your arsenal. The API test kit is easy to use.