GROCO SWEETANK Odor Neutralization System - 12V STK-18 12V. SWEETTANK is standard equipment on THERMOPURE-2 Type-I MSD in GROCO Type-III MSD and is offered in several retrofit kits to fit existing holding tanks.HOW IT WORKSAerobic and anaerobic bacteria coexist naturally in raw sewage but it is the anaerobic bacteria that produce undesirable odors. By inducing a constant flow of air into the holding tank through a submerged aeration tube SWEETTANK produces an oxygen-rich environment in which the anaerobic bacteria cannot thrive thus eliminating unpleasant odors. The heart of the SWEETTANK system is a compact module that operates continuously to deliver air to the holding tank using less than 3-watts of DC power. Specifications for GROCO SWEETANK Odor Neutralization System: Manufacturer: GROCO Color: Black Voltage: 12 volts Package Contents: GROCO SWEETANK Odor Neutralization System GROCO STK-18 12V: SWEETANK Odor Neutralization System - 12V