Dear. Happy New Year. I had sent you the technical datasheet before you approve the price and order. It shows test range on it. As I explained that the acknowledged method to test TSS is gravimetric method. our meter is simple and very fast to get the result. If you use the gravimetric method to calibrate our meter, then you can get the accurate result. But if your water sample is out of test range, you should dilute the water sample. Other equipments are like this. Best regards, Elin Dai