Qualco Chemicals 33862 McCarthy Pools Opening Kit 6 per Case. This Start-Up Kit is effective and safe for all types of pools. This Start-Up Kit is easy to use and will help get your pool ready for the swim pool season. Adding chemicals to the pool at the pool opening will begin the pool water clearing process. The pool water should be clear prior to vacuuming the pool bottom. After clearing the pool water, the additional chemicals will be needed to balance the pool water. Low pH and total alkalinity levels can damage the pool equipment and the pool liner.