Flexible tank covers from Industrial & Environmental Concepts can be customized with viewing windows, sampling ports, service hatches, operator access and piping openings. They can be used on metal and concrete tanks. They contain odors, retain heat, keep rainwater and snowfall out of  tanks, and eliminate algae blooms. They are a solution for aerobic and anaerobic tanks, and they are engineered for local environmental conditions with 15-year service life. The cover systems can be used over clarifiers, sludge tanks, equalization tanks and any tank containing liquid or solids. 952-829-0731; www.ieccovers.com