A water quality sensor is a type of device used to measure and monitor parameters of water quality. These sensors that can read the physical, chemical and biological attributes of water. Water quality sensors are indispensable for assessing the water resources, maintaining human health and protecting aquatic habitat.

pH:

A measure of the acidity or alkalinity of water, which is crucial for aquatic life and various industrial processes.

Dissolved Oxygen (DO): 

The amount of oxygen dissolved in water, which is vital for the survival of aquatic organisms.

Turbidity: 

A measure of the clarity of water, indicating the presence of suspended particles. High turbidity can be a sign of pollution or runoff.

Conductivity: 

A measure of the water's ability to conduct an electric current, which can indicate the presence of dissolved salts and minerals.

Temperature: 

Water temperature can affect the solubility of gases and the metabolic rates of aquatic organisms.

Total Dissolved Solids (TDS): 

The combined content of all inorganic and organic substances dissolved in water.

Biochemical Oxygen Demand (BOD): 

An indication of the amount of biodegradable organic matter in water, which can deplete oxygen levels.

Chemical Oxygen Demand (COD): 

A measure of the amount of organic matter that can be chemically oxidized in water.

Nitrate and Phosphate Levels: 

Important for assessing nutrient pollution, which can lead to eutrophication.

Bacteriological Quality: 

The presence of bacteria such as E. coli or coliforms, which can indicate fecal contamination and pose health risks.

A dissolved oxygen sensor is a device used to measure the concentration of oxygen dissolved in a liquid, typically water. These sensors are essential in various fields such as environmental monitoring, water treatment, aquaculture, and industrial processes. They provide critical data for understanding the health and quality of water bodies by measuring the amount of oxygen available to aquatic organisms.

Measuring dissolved oxygen (DO) in water is crucial for several reasons across different fields.

1. Aquaculture: 

Fish farms and aquaculture operations rely on stable DO levels to maintain fish health and growth rates. Low DO can lead to fish stress, poor growth, or even mass mortality.

2. Wastewater Treatment: 

In treatment plants, DO is monitored to ensure efficient biological processes. Aerobic bacteria in the treatment process require sufficient oxygen to break down organic matter.

3. Predicting Ecosystem Changes: 

Regular DO monitoring can serve as an early warning system for ecosystem changes, such as algal blooms or fish kills, allowing for timely interventions.

4. Indicator of Water Quality: 

DO levels are a key indicator of the health of aquatic ecosystems. Adequate oxygen levels are essential for the survival of fish and other aquatic organisms. Low DO can lead to hypoxic conditions, which can cause stress or death for aquatic life.

5. Biological and Chemical Studies: 

Understanding the oxygen dynamics in water bodies is essential for research in limnology, oceanography, and environmental science. DO levels affect chemical reactions and biological processes in water.

Yosemitech supply one type of Portable Dissolved Oxygen Meter and three types of Optical Dissolved Oxygen Sensors for do measurement and detector in water. Our dissolved oxygen Meters and Sensors provide high-precision measurement and are built to withstand the harshest applications, requiring minimum maintenance and helping you achieve increased efficiency and reduced operating costs. 

From April 21th to 23rd, 2025, IE Expo China 2025 concluded successfully at the Shanghai New International Expo Centre. As a highly anticipated communication platform in the industry, the exhibition attracted exhibitors, experts, scholars, and industry elites from around the world to gather in Shanghai. Through various forms such as cutting - edge technology displays and high - end forum sharing, it created a professional and forward - looking audio - visual feast for the industry.

Suzhou Yosemite Technology Co., Ltd. ("YOSEMITECH"), which has been deeply involved in the water quality monitoring field for over 11 years, always adheres to the mission of "Water Monitoring Made Simple". YOSEMITECH showcased its self - developed water quality monitoring sensors and instruments at the exhibition. As a manufacturer of water quality monitoring sensors, we had in - depth exchanges with domestic and foreign partners and industry peers during the exhibition. It fully demonstrated its profound expertise in areas such as water quality sensor research and development and intelligent monitoring system integration, and continuously empowered global water quality monitoring scenarios with innovative technologies to promote the efficient and intelligent development of the industry.

Y505-A Dissolved Oxygen Sensor Calibration

Required equipments and raw materials
Required equipments: two 1L beakers, one glass stirring bar, one air aeration pump, one set of gloves.
Raw materials: anhydrous sodium sulfite (CAS:7757-83-7), distilled water or deionized water.

Calibration steps
There are two methods of user calibration for the DO sensor: one-point calibration and two-points calibration.

One-point calibration step (change the K value)

Step 1: put an appropriate amount of distilled water or deionized water into a 1L beaker, turn on the air aeration pump and adjust to the maximum gear, introduce air into the water, about 30 minutes, the 100% oxygen water is prepared;

Step 2: connect the cable to the sensor, remove the rubber protective cap on the front end of the sensor and the sponge in the cap, install a black protective cover, put it into the 100% oxygen water, and insert the RS485 to USB connector connected to the sensor cable into the computer;

Step 3: open the SmartPC software on the computer, click “Language” and select “Chinese”, drop down “Port” and select the corresponding COM port, and then click “Connect”, after connecting the sensor successfully, click “Measure”. According to the actual situation (the default salinity is 0ppt, air pressure is 101.35KPa), modify the values of “Salinity” and “Air Pressure” through the “Get” and “Set” options, and then click “Start” to get the real-time measurement of the percentage of DO, DO and temperature;

Step 4: click “Stop” to end the data measuring, then click “Calibrate”, and click “Get” under the “Manual Calibration” interface to get the initial K and B values of the sensor. Click “Restore” under the “Automatic Calibration” interface, select “OK” in the pop-up window, and then click “Get” to check whether the K and B values are restored to the default values (the default K value is 1, and the default B value is 0).

Step 5: under the “Automatic Calibration” interface, change the “Single/First Point Calibration Value” to 100, click “1 point” to do one-point calibration, wait for the values in the pop-up window to stabilize, and click “OK” to complete the calibration. Click “Get” to check whether the K value is written correctly;

Step 6: click “Start” under the “DO” interface to get the real-time measurement of the percentage of DO, DO and temperature, check that the percentage of DO is close to 100% to verify that the one-point calibration is successful.

Two-points calibration step (change the K and B values)

Step 1: put an appropriate amount of distilled water or deionized water into a 1L beaker, turn on the air aeration pump and adjust to the maximum gear, introduce air into the water, about 30 minutes, the 100% oxygen water is prepared. Put an appropriate amount of distilled water or deionized water into another 1L beaker, stir while adding anhydrous sodium sulfite, until anhydrous sodium sulfite is insoluble and solid crystal is appeared, the 0% oxygen water is prepared;

Step 2: connect the cable to the sensor, remove the rubber protective cap on the front end of the sensor and the sponge in the cap, install a black protective cover, put it into the 100% oxygen water, and insert the RS485 to USB connector connected to the sensor cable into the computer;

Step 3: open the SmartPC software on the computer, click “Language” and select “Chinese”, drop down “Port” and select the corresponding COM port, and then click “Connect”, after connecting the sensor successfully, click “Measure”. According to the actual situation (the default salinity is 0ppt, air pressure is 101.35KPa), modify the values of “Salinity” and “Air Pressure” through the “Get” and “Set” options, and then click “Start” to get the real-time measurement of the percentage of DO, DO and temperature;

Step 4: click “Stop” to end the data measuring, then click “Calibrate”, and click “Get” under the “Manual Calibration” interface to get the initial K and B values of the sensor. Click “Restore” under the “Automatic Calibration” interface, select “OK” in the pop-up window, and then click “Get” to check whether the K and B values are restored to the default values (the default K value is 1, and the default B value is 0).

Step 5: under the “Automatic Calibration” interface, change the “Single/First Point Calibration Value” to 100, change the “Second Point Calibration Value” to 0, click “2 points” to do two-points calibration, wait for the values in the pop-up window to stabilize, and click “OK”. Then put the DO sensor into the 0% oxygen water, wait for the values in the pop-up window to stabilize, and click “OK” to complete the calibration. Click “Get” to check whether the K and B values are written correctly;

Step 6: click “Start” under the “DO” interface to get the real-time measurement of the percentage of DO, DO and temperature, check that the percentage of DO is close to 0%, then put the DO sensor into the 100% oxygen water to get the real-time measurement of the percentage of DO, DO and temperature, check that the percentage of DO is close to 100% to verify that the two-points calibration is successful.