System and Use Cleans and descales every AIR-O-SWISS product, and cleans mineral build-up. 2 Simple and safe to use - EZCal ensures a clean humidifier and continuous high performance. 1 One box includes 3 individual packets, use just one packet per cleaning. 4 For best results use EZCal every two weeks depending on the water hardness. 7 Instructions for use are on the packet. Only use 1 packet for 32oz of water. Do not change the ratio. Do not run the unit when using EZCal. Thoroughly rinse the base with potable water and make sure no EZCal residues remain in the base. 6 Select AIR-O-SWISS humidifiers include a sample package of EZCal. 5 EZCal is safe to use on other humidifier brands.