[5-in-1 Aquarium Salinity Digital Tester] ①Measure water temperature in degrees Celsius and degrees Fahrenheit ②pH(Pondus Hydrogenii) ③salinity ④TDS ⑤EC,Simultaneous display of 5 parameters, intuitive and convenient.Equipped with battery indicator to control the battery status at any time, No operation, automatic shutdown after 5 minutes, saving energy and electricity.At the same time, there are functions such as automatic range switching and automatic temperature compensation.[Switch Display Interface and Automatic temperature compensation] Can switch the direction of the LCD screen according to preference or use environment,the switching sequence is [General]-[]-[Left Hand]-[General]. tester can automatically compensate for temperature errors based on changes in water temperature,more accurate measurement values.[How to Use] Power on/off:press and release the button 1s to turn on or off the device,automatically turn off after 5 minutes of inactivity. display interface switching:press button for 2s and release to switch between display mode. Function selection:press the button for 5s and release to enter the function selection menu.there are three functions to choose from:pH-CAL,EC-CAL.RESET,stand for pH calibration,EC calibration and restoring to factory.[Widely Used In Life and Aquariums] In aquarium①measure the water temperature ②measure the pH.The pH value of water is between 6.5 and 9,and the seawater is between 7.5 and 8.5.③Test the total solid solubility of water.It is recommended not to exceed 800ppm for fish farming in water(without salt).④Test the conductivity of water.The more harmful substances or pollutants in the water,the higher the conductivity,raise marine fish and coral,recommended to range from 1.020 to1.024 ms/cm.Colour:BlackMaterial:PlasticPackage Contents:1 * salinity tester1 * English manual1 * usb cableOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.