This end of season additive was created keeping in mind that most pools are closed longer than they are open; strong and long lasting are key. The ProTeam Winter Kit uses the proven Supreme borate technology that suppresses all growth in pool water during closing. The swimming pool will remain beautiful through winter. This winter kit is compatible with Biguanide, Bromine, Chlorine, Copper/Silver and Ozone treated swimming pools. Experience an easy spring start-up, saving time and money. And since borates are added to the water, this winter kit has the added benefit of lowering sanitizer cost for the next pool season. Long lasting, dissolves quickly in water - 1 pail treats up to 12-15,000 gallons of pool water all winter.