Sensor Care

Video: Membrane Replacement for TOUGH series DO Sensors

Not sure how to replace the membrane on your Turtle Tough Tough Series Dissolved Oxygen (TT-TOUGH-DO-M4M) sensor? Learn how easy it is, with our step by step video. 

You will need:

  • Tough Series dissolved oxygen sensor
  • 1M Potassium Hydroxide solution
  • DO membrane replacement kit
  • Sharp blade beaker (100ml)
  • Membrane alignment guide
  • Tissues
  • Water



  1. Remove the membrane by taking the components on the tip of the sensor.
  2. Remove the O-rings (for easy removal: run water across the tip to lubricate the tip and slide the collars and then remove the o-ring). 
  3. Remove the old membrane and rinse the tip to eliminate the potassium hydroxide on it. Take a tissue and dry it to remove any dirt or debris left.  (Make sure the tip it's nice and clean).
  4. Get the new membrane out and place it onto the membrane positioner. Centred it over the top and place the collar down firmly until you have a nice tight membrane.
  5. Grab the potassium solution. Hold the sensor in a vertical orientation with the tip upwards and place one drop of electrolyte on top of the tip to get a perfect seal.
  6. Drop the membrane positioner in place to get the perfect tension on top of the tip of the sensor.
  7. Grab one of the collars and push it down into position.
  8. Remove the membrane positioner.
  9. Slide the collar down in place pushing it until you reveal the channel for the o-ring.
  10. Slide the o-ring into place followed by the other collar into place.
  11. Rinse and dry the tip off.
  12. Remove the excess of the membrane using a sharp blade score around the bottom of the red collar.
  13. Replace the protective cap and you are ready to go!