The 2 standard refill solutions for pool & spa chemical test kits
1/2 ounce dropper bottle of OTO (Orthotolidine) Chlorine Test Solution
1/2 ounce dropper bottle of Phenol Red pH Test Solution
The 2 standard testing solutions that are used for measuring and maintaining the proper Chlorine, Bromine and pH chemical levels in swimming pools and spas
5 drops of each solution are typically mixed in a test tube block along with pool water to check the Chloride, Bromine and pH readings