Read up on the chemistry of chlorine and break-point chlorination at our Chloramine Info page.
Shock the pool when:
- Combined Chlorine (also called Chloramines) levels are Above 0.3ppm, as determined by your DPD Test Kit. If your eyes are burning, and the smell of chlorine is strong, chloramines may be high.
- Your swimmer load has been considerably heavy for a sustained period of time.
- You want to raise the chlorine level quickly to clear the water or kill algae.