A memory device including at least one memory location for storing information representing data written using a first encryptiondecryption method, and a read channel using a second encryptiondecryption method for reading and decrypting information as written. The thermally stable region has a microstructure comprising a plurality of diamond grains bonded together by a reaction with a reactant material. The present invention provides a reliable, cost-effective means by which to decrease the algae growth generally associated with water reservoirs. A third control system can both monitor sensed data and the movement commands of first and second control systems, and can monitor the resulting physical movements.