In The Swim Pool Closing Kit - Winterizing Chemicals for Above Ground and In-Ground Pools - Up to 15,000 Gallons Multicolor

Labor Day has passed, the water is cooling, and the cover is about to go on for the season. This closing kit from In The Swim gathers the winterizing chemicals for one shutdown into a single box, sized for pools holding up to 15,000 gallons and suitable for both above ground and in-ground installations.

• 1 quart Winterizer
• 1 quart Winter Stain-Away
• 2 pounds chlorine free pool shock
• 1 Winter Sorb
• 1 winter pool floater

The shipped package measures 13.6 by 8.8 by 8.6 inches and weighs 11.24 pounds. Pool volumes that fall between listed kit sizes should be matched to the larger option, and owners of pools above 35,000 gallons can combine more than one kit to cover the full water volume.

Before adding the chemicals, test and balance the pool water one final time, targeting proper pH and alkalinity levels, since balanced water at closing reduces the chance of staining and scale buildup over the winter months. The chlorine free shock is designed to oxidize organic contaminants without spiking the chlorine level, which matters when you are closing rather than opening, because a heavy chlorine dose at shutdown can bleach a vinyl liner or damage certain pool covers. The Winter Sorb works by absorbing non-living organic material that would otherwise feed algae growth beneath the cover, and the floater releases a measured amount of sanitizer slowly over the off-season. Following the application order recommended on each product label is worth the few extra minutes it takes.

This kit suits pool owners who want to avoid sourcing each winterizing chemical separately and risk mismatched quantities. Because the contents ship together in a single box, storage between purchase and closing day is straightforward: keep the package in a cool, dry location away from sunlight and out of reach of children. When comparing closing kits across brands, the most useful thing to verify is the rated gallon capacity against your actual pool volume, since undersizing a kit is the most common mistake buyers make at this stage of the season.