Pool well-filled with water – wonderful. How much is contained in samples or products, however, needs to be determined by many labs and manufacturers with much greater precision. In many cases, loss on drying (LOD) techniques will do the trick. But if other sample constituents evaporate alongside water, the result will be inaccurate. Continuous monitoring also requires specific solutions. As a consequence, there is a diverse array of techniques to choose from, each with their own merits.