The Lochinvar & A.O. Smith 100208333 Limestone Neutralizing Kit is a condensate treatment accessory designed to reduce the acidity of wastewater produced by high-efficiency gas-fired boilers and water heaters. It works by passing acidic condensate through limestone media, which raises its pH level before the water enters the drainage system. This helps minimize corrosion in drain pipe... https://www.partshnc.com/100208333-lochinvar-ao-smith-lime-stone-neutralizing-kit