instant reading wrong

  1. M

    Aqua-PL- plus ppm instant reading in (-) is half of (+) & read very low vrs confirmed actual

    system consistently reads 600 to 800 ppm below confirmed actual Also, when I reset instant reading & countdown then settles. The (-) is consistently 1/2 or less of the (+) reading as follows; also note big difference in amperes, these should be the same Values just reverse. a) -27.2v. -3.9amp...