Balls for heat retention 

1. Heat retention. As the balls cover more than 90% of the surface area, they provide an insulation blanket on the tank.
2. Odor control. Less exposed surface area results in less odor emission
3. Algae control. The balls block the UV from penetrating the water.
4. Bird control. The balls camouflage the water surface from waterfowl thus preventing unwanted birds from using or contaminating the water.
5. Evaporation control. Covering the water surface minimizes evaporation and water loss.
6. Vapor containment. Reduces chemical vapor emissions. 

Physical and Chemical Properties of the Plastic Material: