Monitor the PH/EC value of hydroponic nutrient solution to that plants have a suitable growth environment. Fish tank PH/salinity tester: monitor the growth environment of fish, prevent and treat fish diseases, purify water and maintain water cleanliness, suitable for freshwater fish, marine fish, ponds, etc. Swimming pool pH salinity tester: ideal range for saltwater swimming pools (pH: 72-7.8; salt: 2700-3400ppm). This 5-in-1 high- digital water quality tester can be used for the following applications: food salinity, aquaculture, drinking water, laboratories, swimming pools, fish tanks and other water quality testing. Check the TDS value of drinking water. The backlight design allows measurements in dimly lit environments., Manufacturer: Ounfhtrttk