HANNA HI 98129 Waterproof pH/EC/TDS/ºC/ºF Combo Tester
or
oakton waterproof PTTestr 35(pH/TDS)

cause i just want a pen to read tds(tds is ppm rite like 200 or 1400 ) i dont want the two numbers like 0.4 or 2.8
Felixthecat Reviewed by Felixthecat on . HANNA INSTRUMENT HANNA HI 98129 Waterproof pH/EC/TDS/ºC/ºF Combo Tester it's the black one what you guys think about this product is it better to buy it separate or 3in1 Rating: 5