The MA911B/2 electrode requires proper care to maintain accuracy and extend service life:

Filter Replacement Schedule

large or small

The two parts of the pH probe that cause problems are the glass sensing bulb and the reference junction

Alexapure Survival Spring Personal Water Filter

Milwaukee MW802 PRO pH/EC/TDS Combo Meter - 3-in-1 with ATC union tee connector The MA911B/2 electrode requires properMilwaukee MW802 PRO 3 in 1 Combo Meter: Professional pH, EC & TDS Testing The Milwaukee MW802 PRO is a professional grade combo meter designed specifically for growers who demand precision. Measure pH, electrical conductivity (EC), and total dissolved solids (TDS) with a single integrated probe. Built for hydroponics, aquaponics, and greenhouse operations, this meter delivers lab quality accuracy in a rugged, portable package. Key Benefits 3 in 1