Tests for: 2 important chemistries, Total & Free Chlorine so you know when to shock

ShockChek is the fast, easy way to determine if you need to shock (or super chlorinate) your pool or spa. Just dip a strip and compare to color chart which indicates a simple Shock or Okay result. Shocking is a necessary maintenance step that keeps the water clear of harmful contaminants that can cause irritation and spread water-borne illnesses.