Caldera Spa Monarch Test Strips 5 Way Item #74365 Description: There are numerous factors can affect the bromine, chlorine, alkalinity, calcium hardness and pH levels in your spa. These 5-Way Test Strips will accurately measure these levels and enable you to determine how to correct and balance your water. Contains 50 5 way test strips Tests For: Bromine Chlorine PH Alkalinity Hardness Features:. Ideal for use in spas, hot tubs and swimming pools. Fast and simple Accurate These test strips work with chlorine as well as ozone sanitizers About Caldera Water Care Products: Caldera Spa’s efficient and simple hot tub water care systems make it easier than ever to keep the water in your hot tub fresh and crystal clear.