Check the listing for details. Milwaukee CD610 Total Dissolved Solids High Range for Aquariums. Condition: New. Listed at 45.00 USD. The Milwaukee CD610 Total Dissolved Solids High Range (PPM) Pen is designed for aquariums, pools and education and many other applications. The CD610 helps make sure that you keep your fish tank water clean and healthy. It is a cost effective tool for teacher's science labs. Keep PPM in your target range to help your achieve better results. DESIGN FEATURES Measures Total Dissovled Solids (PPM) direct and with automatic temperature compensation. Ideal range for aquariums and pools (0 to 10000 ppm). Units in ppm easily convertable to uS/cm. Factory calibrated with the ability to recalibrate if needed. Automatic Temperature Compensation (ATC). 350 hours continuous use (4 x 1.5V batteries included). Simple one point calibration.