Helps you duplicate the natural habitat of your fish to prevent stress, keeping them healthy!
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!
SIZE:
| Item | Quantity |
|---|---|
| Test bottles | 2 |
| Test tubes | 2 |
| Instructions | 1 set |
FAQ
How often should I test my aquarium’s GH and KH levels?
We recommend testing your aquarium’s GH and KH levels once a week to maintain stable water conditions and support fish health.
Can this test kit be used for both GH and KH measurements?
Yes, this test kit is designed to measure both general hardness (GH) and carbonate hardness (KH) accurately.
Are the test tubes reusable?
The test tubes are single-use and should be discarded after each test.

Hannah Scott –
Easy to use and very accurate. I’ve been using this kit for a few months now and my fish seem more active and less stressed. The instructions are clear and the results are consistent.
Jack MacLeod –
Works well for weekly checks. The test tubes are clean and the reagents don’t stain. My planted tank has stayed balanced without any issues.
Rose Buckland –
Great value for the price. I tested my water every week and noticed a significant improvement in water stability. My fish have not shown any signs of illness since using this kit.