HI-Test is an alkaline tile and grout cleaner that is also a superior natural stone cleaner. It is safe on acid sensitive surfaces such as marble, tile, stone, grout, travertine, terrazzo, and more. It may be used for complete restoration or daily maintenance. It is biodegradable, low foaming and extremely free rinsing. This is our #1 selling natural stone and Tile cleaning solution by Newline.