Tannin is a natural organic material that is the by-product of nature s fermentation process created as water passes through peaty soil and decaying vegetation. Tannins create a light yellow to dark brown discoloration of the water and cause yellow staining on fabric fixtures and laundry. Tannin-based formulations are used for the prevention of scale and corrosion in steam boilers closed cooling systems and steam locomotives. The AE2TN – TANNIN TEST KIT is a titrimetric one and has reagents for two ranges in the same kit making it portable and user-friendly.