I have a few generic TDS meters but I am looking for something that will provide a more precise result. Below is my understanding of what Hanna has to offer. I welcome input on whether my calculations are correct and also on which of the two testers you would recommend (or possibly something else altogether). Thanks
Based on my research, it looks like the Hanna HI98309 Ultra Pure Water (UPW) Tester (https://www.hannainst.com/ultra-pure-water-upw-tester-hi98309.html) is the most precise. Its EC Range is 0.000 to 1.999 μS/cm. Assuming the EC to TDS conversion factor is .5 (as I believe it is for their other TDS meters), the TDS reading would max out at just under 1 ppm (.9995 ppm). With an EC Accuracy of ±2% F.S., I think this works out to be ±.02ppm. Thus a reading of 0 TDS could be .02 ppm.
The next best, and maybe the more appropriate TDS meter, is the Hanna HI98308 Pure Water Tester (https://www.hannainst.com/hi98308-pure-water-tester.html). Its EC Range is 0.0 to 99.9 μS/cm. Assuming the EC to TDS conversion factor is .5 (as I believe it is for their other TDS meters), the TDS reading would max out at just under 50 ppm (49.95 ppm). With an EC Accuracy of ±2% F.S., I think this works out to be ± 1ppm. Thus a reading of 0 TDS could be 1 ppm.
Based on my research, it looks like the Hanna HI98309 Ultra Pure Water (UPW) Tester (https://www.hannainst.com/ultra-pure-water-upw-tester-hi98309.html) is the most precise. Its EC Range is 0.000 to 1.999 μS/cm. Assuming the EC to TDS conversion factor is .5 (as I believe it is for their other TDS meters), the TDS reading would max out at just under 1 ppm (.9995 ppm). With an EC Accuracy of ±2% F.S., I think this works out to be ±.02ppm. Thus a reading of 0 TDS could be .02 ppm.
The next best, and maybe the more appropriate TDS meter, is the Hanna HI98308 Pure Water Tester (https://www.hannainst.com/hi98308-pure-water-tester.html). Its EC Range is 0.0 to 99.9 μS/cm. Assuming the EC to TDS conversion factor is .5 (as I believe it is for their other TDS meters), the TDS reading would max out at just under 50 ppm (49.95 ppm). With an EC Accuracy of ±2% F.S., I think this works out to be ± 1ppm. Thus a reading of 0 TDS could be 1 ppm.