Kohler does not recommend the usage of in-tank toilet cleaners. These cleaners have chemicals that can eat away at plastic and rubber parts causing the toilet parts to weaken. Kohler does not warranty parts when using in-tank cleaners.
Kohler does not recommend using chloramines in toilet tanks. Chloramines, a combination of chlorine and ammonia, will deteriorate plastic components and cause rust formation on metal components. Kohler does not warranty parts that have been exposed to chloramines.