Your meter is only as accurate as the electrode (probe/sensor) is clean. A dirty electrode or an improperly cleaned one will never give you reliable readings. Apera's electrode cleaning solution helps you thoroughly remove contaminants on pH/conductivity/ORP electrodes, maximizing the service life and maintaining the accuracy. Electrode cleaning is a fast and effective routine that should be performed on a regular basis. Simply immerse the electrode in Apera's cleaning solution for 15 to 20 minutes (remove the sensor shield if there is one), most mineral deposits, protein-containing contaminants, or other coatings will be dissolved. After the soaking, rinse off the remanent with a soft brush and clean water. Then calibrate your meter again before measurement.