Water testing · Liquid test kit
API KH / Carbonate Hardness Test Kit
Tests KH only, from a 5 mL sample of tank water.
Liquid drop test for carbonate hardness (KH), the buffer that keeps pH from swinging, in fresh or salt water.
Consider: KH only. If your fish or plants need a set hardness, API’s GH & KH kit tests both.
US version. Check what’s in the box before you buy.
What it tests
- Tests for
- Carbonate hardness (KH)
- How to read it
- Fill the test tube with 5 mL of tank water, hold the bottle upright and follow the drop directions in the booklet.
Before choosing this model
- Test weekly, as API advises: water with low KH can swing in pH quickly.
What API doesn’t publish
- API doesn’t print how many tests the bottle holds or the range it reads. Check the booklet.
In a new tank the readings that matter most are ammonia and nitrite, so check the kit reads both, or add a test that does: see how to test your water.
Have a reading? See what it means for your fish and what to do today.
Included items & upkeep
- 1 KH test solution bottle
- instruction booklet
- 1 capped test tube
Plan for the routine work
- Rinse the test tube with water right after each test, as API advises, so the reagent doesn’t stain it.
Check the use-by date printed on the pack before you trust a reading: old test solutions and strips can read wrong. Replace the kit once it is past that date.