Membrane covered optical CO2 sensor for aquaculture
Online determination of the dissolved carbon dioxide in water

The measurement of the dissolved carbon dioxide gas (excluding HCO3- and CO32- ) in the water in fish farms is one of the most important parameters for the success in aquaculture. Until now the so called m-value method has been used, which has some disadvantages. Apart from the very time-consuming manual analysis, the m-value method is not only influenced by CO2 , but also by all the other compounds with influence to the pH-value (e.g.phosphates, silicates, hydrogen carbonate, carbonate). Additionally, the m-value method requires sampling, which may lead to errors too. On the other hand, a direct reading sensor is required to allow the control of the conditions in the water.

Main features of the Carbon Dioxide Sensor:
- submersible direct reading sensor for water and air
- detects only dissolved CO2 gas
- no signal interferences to silicate, phosphate, HCO3- and CO32-
- built-in reference measurement for superior stability

Technical data of the membrane covered optical carbon dioxide sensor:
Carbon Dioxide:
• Measuring ranges: 3 mg/l, 5 mg/l, 8 mg/l, 12 mg/l, 30 mg/l, 50 mg/l, 80 mg/l, 170 mg/l, 340 mg/l
• Accuracy: ± [1.5% FS + 2% of reading]
• Temperature dependence of output: - 0.3% of the measuring per °C
• Pressure dependence: 0.15% of reading/hPa
• Longterm stability: < ± 5% FS/2 years
General:
• Dimensions: 240 mm length, 70 mm diameter
• Housing material: Nylon 6
• Connector: Subconn MCBH4M
• Power supply: 11-20 V DC or 18-30 V DC
• Power consumption:< 2.5 W
• Recommended external load: current output: max. 200 Ohm; voltage output: min. 1 kOhm
• Warm up time: < 15 minutes
• Max. Depth: 3 m
• Available analog outputs: 0...20 mA, 4...20 mA, 0...1 V, 0...2 V, 0...2.5 V, 0...5 V
• Temperature range for storage and measurement: 0...30°C