Gross! Also… a substantial portion of the granules get flushed down the rest room. I haven’t researched those particularly… but I can’t envision that it's great to your plumbing. The granules appear to be plastic. Possibly they biodegrade? Idk.. not my fav. We have been searching in to other systems. https://nanobookmarking.com/story20110859/the-2-minute-rule-for-petkit-purobot-uae