SODIUM: 9245 Single-Channel, On-Line, Sodium Analyzer. HARDNESS: SP 510 Hardness Analyzer. DISSOLVED OXYGEN: Sensor Hach LDO Dissolved Oxygen, Hach Polymetron Oxygen Scavenger Analyzer 9186.HACH Orbisphere G1100 Luminescent Dissolved Oxy( LDO) Sensor. SLUDGE LEVEL: Sonatax sc Sludge BLanket Level Probe