Assmann Corp.: Open-top tanks molded from a choice of virgin high-density cross-link or NSF/ANSI 61-certified linear polyethylene are used as day tanks or mixing vessels. These flat-bottom vertical tanks are equipped with shoe-box-style covers and are molded with a stiffing lip on top to give the tank rigidity. Features include uniform thickness, optional stainless-steel and mild-steel epoxy-coated agitator support stands, and optional stainless-steel or polyethylene hinge.