The Retro-Air Rejuvenator System from Septic Services 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 as well as other secondary treatment systems and is recommended in aeration systems that are prone to backup. It aerobically restores failed anaerobic installations or prevents failures in new systems by delivering a constant flow of air to the diffuser, according to the maker. Over time, aerobic bacteria consume the biomat, allowing the soil to absorb effluent once again. It is quick and easy to install and requires minimal maintenance. 800/536-5564; www.retro-air.com.