PH
PH-it (the aqueous indicator) showing the water level of its acidity or alkalinity. In the water of the swimming pools, the pH must be maintained within 7.2-7.6. Within these limits, the system is working optimally. Also this is the best pH for the eyes and skin of swimmers. To keep the pH-it within these limits, check their level every day using CTX10 (pH "-") and CTX20 (pH "+").