Gemini² Tanks have the same great features and benefits as cylindrical Gemini Plastic Tanks but have larger capacity per footprint. Gemini² Tanks have 22% more capacity than cylindrical tanks of the same size. Gemini² Plastic Tanks are an excellent choice when you’re looking for safe storage of chemicals and other products where a Secondary Containment Tank system is required. Not NSF/ANSI 61 compliant at this time.