The Retro-Air Rejuvenator System from Septic Services helps return a failed existing septic system back to optimal flow and performance. It can be used in new or existing septic systems and can be installed in single- or multiple-compartment septic tanks. It is designed to eliminate clogged drainfield biomat, and the maker recommends it for aeration systems that are prone to backup. The system uses the aerobic process to restore failed anaerobic installations or to prevent failures in newly constructed septic systems by delivering a constant flow of air to the diffuser. It is easy to install, requires minimal maintenance and is available in several models. 800/536-5564; www.retro-air.com.