Yellow 4-in-1 is designed for customers who use chlorine in their pool or spa: the go-to product for testing the most critical parameters in your pool. You'll find the easy-to-use flip-top cap conveniently dispenses one strip at a time. AquaChek Yellow is a great choice when getting started with pool testing.

Tests for: Free Chlorine, pH, Total Alkalinity, Stabilizer (Cyanuric Acid)