API GH & KH General & Carbonate Hardness Freshwater Aquarium Test Kit

Rated 4.7391 out of 5 stars
$11.99Chewy Price
$16.78Chewy Price
$11.39Autoship Price
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About This Item


  • Contains 1 API GH & KH Test Kit Freshwater Aquarium Water Test Kit, including 2 bottles of testing solution and 2 glass test tubes with cap.
  • Promotes a more natural habitat and is ideal for a planted aquarium.
  • Helps prevent wide, abrupt pH level changes from low KH levels.
  • Helps fight crusty calcium buildup on the hood and glass of the aquarium.
  • Easy to use and comes with everything you need.

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Play Video: Learn More About API From Our Team of Experts
Learn More About API From Our Team of Experts

Make your fish feel right at home by softening your hard water with API's Water Softener Pillow.

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Total Price: $37.47

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, Goldfish, Tropical FreshwaterBetta, Bottom Feeder, Cichlid...Betta, Bottom Feeder, Cichlid, Goldfish, Tropical FreshwaterBetta, Bottom Feeder, Cichlid, Goldfish, Tropical FreshwaterBottom Feeder, Discus, Goldfish, Marine Invertebrate
Aquarium TypeFreshwaterSaltwater, FreshwaterFreshwaterFreshwaterSaltwater, Freshwater, Pond

Questions & Answers

2 Customer Questions

How many tests are there in total
Answer by ChewyApr 18, 2022
Most of our API test kits will have a test number rating on the box. But the GH & KH test kit does not. This is because a variable amount of drops is dispensed for each test. More tests will be able to be performed in softer water than harder water.

Do these tests not come with a color chart?
Answer by ChewyJan 21, 2023
This kit contains 2 test bottles, easy-to-ready instructions, and glass test tubes. It does not include a color chart.

ReviewsWrite a Review

Rated 4.7391 out of 5 stars
23 Ratings
Would recommend to a friend

22 Customer Reviews

Rated 5 out of 5 stars
By Happy on Jan 21, 2022

Works as it says

Chewy is the best...I ordered as of my fish aquarium supplies from them.. fast shipping best prices around. An amazing customer service.. I would recommend this test kit for anyone who has aquariums

Rated 5 out of 5 stars
By Kitty13 on Jan 19, 2022

Works well!

Bought this to test my tap water's hardness for my shrimp and snails. Directions are easy to follow and everything you need is included. Tests seem to be accurate so far based on other tests I've done.

Rated 4 out of 5 stars
By autumn on Sep 18, 2021

tells me what I need to know

One of my test tubes came cracked (would have gave 5 stars otherwise) but the other tube was fine I didn’t realize there were two in there but overall a good product.

Rated 5 out of 5 stars
By Obiewan on Sep 30, 2021

Great Product

Great product works amazing to tell the hardness of the water is a life saver for soft water Fish

Rated 5 out of 5 stars
By TJay on Apr 15, 2021

It tells me what I'm looking for

It does not work like the ones in your API Master Kit, it does have a color chart like you would expect, it indicates readings based on number of drops and when the test tube converts to another color. Read the instructions as you should, and it'll do what you expect this test kit to do.

Rated 4 out of 5 stars
By rebeccarose on Mar 4, 2021

Arrived in package badly but kit is amazing

Opened the package and everything was out of the box, but thankfully the glass test tubes didn’t break. The kit itself is easy to use and gave me a reading that seems accurate for my tank. I am a shrimp keeper so a kit like this is critical to my babies survival! Thanks again Chewy <3

Rated 5 out of 5 stars
By DanielleH on May 20, 2021

Exactly as pictured.

Gets the job done. Accurate and has detailed instructions on how to use it.

Rated 5 out of 5 stars
By Aleviltona on Feb 13, 2021

Great item

Easy to use like all the other API items. One of the bottle was leaking and lost about 30% of the fluid. I contacted chewy and they sent a replace within a few hours. Very happy with the website.

Rated 5 out of 5 stars
By easttexasbirdman on Apr 17, 2021

Tried and True!

Very helpful in keeping my 50 gallon planted freshwater tank happy and healthy!

Rated 5 out of 5 stars
By Demeter on Jun 29, 2020
Top 1000 Contibutor

Perfect for trouble shooting problems.

I started having molting issues with my 36gal invert tank. Decided to get the test kit to make sure all was in order. After finding out the GH and KH was just fine I discovered the problem was my liquid fertilizers. It's always good to have test kits around when things start going south.