Gravity Analog Dissolved Oxygen Sensor SKU SEN0237
linges06 2025-07-31 14:21:02 109 Views3 Replies hi sir/madam,
Hi, my name is Linges. I have a question about the DO (Dissolved Oxygen) sensor. I want to measure the oxygen level in a shrimp tank. Do I need to use the membrane cap, or can I avoid it? Should I fill the cap with NaOH solution before placing the sensor in the tank?
Also, I’m confused about the calibration process. Why do we need to fill the membrane cap with NaOH for calibration instead of just placing the sensor directly into the water?
Calibration has to be done after the membrane cap is correctly filled with NaOH solution. Calibration tells the sensor how its electrical output voltage relates to known oxygen concentrations. If there's no NaOH solution, there's no reaction, no valid voltage signal, and therefore no way to calibrate.
Tonny12138 This dissolved oxygen sensor works because oxygen molecules diffuse through the thin membrane cap and react with special electrodes inside the probe. That reaction happens within a specific alkaline electrolyte solution (the 0.5 mol/L NaOH) and generates a tiny electrical signal proportional to the oxygen level. Without that NaOH solution filling the cap, the necessary chemical reaction simply can't happen, and the sensor won't produce any signal at all. The membrane cap has two critical jobs: it securely holds the NaOH solution around the electrodes, and it acts like a selective barrier, letting oxygen in while keeping water, dirt, and other contaminants in your shrimp tank out. Skipping the cap and putting the bare electrodes directly into your tank water would quickly ruin them
Tonny12138 If I fill the membrane cap with NaOH and place the sensor in the shrimp tank, will it affect the shrimp? Or is it safe? I'm a bit scared that the NaOH might harm them. because I'm going to use this for 2 months.
