Jon I was interested in getting a TDS meter if you get a few orders and get free shipping. I will be getting one soon.
"DM2 Inline meter displays TDS levels of feed water and product water. Auto-off function conserves battery. Dual Range - Measures from 0-999 ppm, with a resolution of 1 ppm, from 1000 to 9990 ppm in 10 ppm increments. Factory calibrated with 342 ppm NaCl solution. Can be recalibrated with a mini-screwdriver. Includes 1/4 inch John Guest fittings. Also available with 3/8 inch fittings.
Differences from the DM1
Stronger, water-resistant casing. Calibration can be done individually or simultaneously on each probe. Lager display. Longer, waterproof, shielded cables. Variable mounting bracket.
BFS-252 DM2 Dual Inline TDS Meter - $49.79"