Bests & Worsts Reviews from Amazon

The pH pen came with out the calibration solution, but after vigorously researching how to calibrate the TDS&EC Meter I came up with nothing. I tested the EC meter and it was about 100 ppm below the calibration solution at 77°F. The only thing that I could find is that the TDS & EC meter was factory calibrated. ***Would like to update my review*** after receiving a new meter This one is perfectly working great! The customer service was actually awesome, because when I initially gave them a one star rating I was contacted by a representative from the #VIVOSUN and I was offered a new TDS meter for free. It really says a lot about a company that will reach out to their unsatisfied customers for a combo set that cost about $15.