One simple pill keeps your pool warmer by spreading an invisible layer of non-toxic, biodegradeable film across the water. Cuts down on cooling evaporation making it 60% as effective as a traditional solar blanket. Simply drop Solar Pill into your pool?s skimmer and its special time-released delivery system will keep your pool warm for 30 days. Not affected by automatic pool covers. For above ground pools (up to 12,000 gallons). Saltwater compatible. Imported.