HI 758 Marine Calcium Checker

Range 200 to 600 ppm Resolution 1 ppm Accuracy @ 25° C ± 6% of reading Light Source light emitting diode @ 610 nm Light Detector Silicon Photocell Environment 0 to 50 ° C ( 32 to 122 ° F) ; max 95% RH non-condensing Battery Type ( 1) 1.5V AAA Auto-off after 10 minutes of non-use Dimensions 81.5 x 61 x 37.5 mm ( 3.2 x 2.4 x 1.5" ) Weight 64 g ( 2.25 oz.) Method adaptation of the zincon method
testing instrument