Enviro aerators from Blue Diamond Pumps are designed for biological aeration in domestic wastewater treatment units and ATUs. They use an electromagnetically operated diaphragm to eliminate sliding parts and minimize wear and tear. They incorporate energy-efficient motors and have a weatherproof compact alloy casing. A range of models are available in steps from 8 to 53 gpm. They are CE and UL approved. A built-in fail-safe alarm detects low pressure in the air line, alerting users with a loud buzzer and LED warning light. It is also available with a 230V signal wire for activating an external alarm system. 770/831-1122; www.bluediamondpumps.com.