Ace Roto-Mold 1,000-gallon septic tanks from Den Hartog Industries are designed to be strong and easy to install. Manufactured from high-density polyethylene with UV inhibitors, they have a horizontal flow designed for belowground installations up to 36 inches. The AST1000-2 double-compartment tank has been tested by NSF to meet the IAPMO Z1000 and CAN/CSA-B-66 standards. It has a trapezoidal deep-rib design and an interior divider panel, and a custom-molded gasket in the lid. Manufactured from extruded nitrile rubber, the gasket snaps into the lid to ensure a watertight seal. The tank divider panel slows the flow of wastewater and directs it to the middle of the tank so wastewater can separate from solids. An outlet baffle allows partially treated liquids to flow out for further treatment. 800/342-3408; www.denhartogindustries.com.