SOLAR COVER: An option that helps heat the pool water. (Also called a Bubble Cover or a Solar Blanket). Solar covers have a smooth side, while the other side is full of air bubbles. Always lay the solar cover on the water with the bubble side DOWN (facing the water). As the sun penetrates the cover, it will heat the water. During the evening, the solar cover will retain any heat that it previously captured. NEVER use the solar cover after shocking the pool with a chlorine-based shock. The super-chlorinated water will disintegrate the bubbles, rendering the solar cover less effective. Leave the solar cover off for at least 8 hours after shocking the pool. Even with a heater, a solar cover is a wise investment. If you purchase a solar cover, it is a good idea to also purchase a SOLAR REEL.