When storing synthetic stones, you must differentiate between those that need to be stored dry and those that can be permanently stored in water, preferably in a sealable
Storage in water: King, Sun Tiger, etc.
Dry storage: Shapton, Suehiro, Sharpening Stone by Naniwa, Jinzo, etc.
A dash of vinegar or disinfectant should be added to the water to prevent algae growth. Household cleansers, however, should not be used since they attack the stone‘s bonding. In order to prevent cracking, sharpening stones should never be exposed to frost! When using highly calcareous water, do not let the stones dry out too often; otherwise, lime builds up and reduces the stones‘ efficiency. Sharpening stones should be handled carefully. Keep them flat, clean and free of oil since oil prevents the stones from absorbing water, limiting their abrasive effect.