A TDS meter is an inexpensive and convenient digital tool to instantly check your overall water quality. TDS = Total Dissolved Solids, which is any salt, metal or mineral in the water. With the push of a button, the TDS can tell you your overall water purity level, which will be displayed on the screen in ppm (parts per million). The lower the TDS level, the purer the water, with 0 ppm being pure H2O. The TDS is great for checking your tap water quality, or knowing when to change a filter. (The meter does not test for biological contaminants.) The TDS is a great tool for drinking water, water filtration and purification, colloidal silver, hydroponics (test your nutrients), aquariums, RO/DI systems, pools and spas, commercial and industrial applications and more. The TDS is a rugged model that includes a protective carrying case. This is the world's most popular handheld TDS meter for industry professionals. Ideal for Commercial Use Its Includes a Carrying Case with Belt Clip Hold Function: Saves Measurements.The quick results tells you about the water/solution in a way which is easy to read and understand from the large display screen.Taking temperature measurements once the meter is on, the temperature function can be used at any time, in or out of liquid. Press the temp button and display will switch to temperature which shows temperature in celsius when wish to return to TDS mode, press the TEMP button.Instrument Easy calibration of total dissolved solids (TDS), temperature (temp) and parts per million (PPM) in home or office, swimming pools, aquariums, ponds, fresh water sources from creeks, rivers, wells, rain water storage, greenhouse, garden or horticulture, camping or travelling.This TDS Meter for test the filter water quality purity, check the performance of your water filter, check for hardness (1grain 17PPM), make sure you always drink pure water.