STRONGEST START-UP POOL SHOCK. Compare to Sock It, Burn Out®, Sun Burn®, Super-Chlorinator®, and Power Powder®. This powerful 65% available chlorine zaps organic pollutants, bacteria, and algae from your pool water. A quick chlorine boost at an economical price. Perfect for spring start-up! Active ingredient: Calcium Hypochlorite. This unique, quick-dissolving formula does not require pre-mixing and will not cloud your pool water or bleach your vinyl pool liner. Burst is also pH-neutral, so it will not affect pH levels, cutting down on the expense of balancing pool chemicals. Super strong 56% available pool chlorine.