Additional You can now wind up the Secchi disk mechanism. Acidity If you used pH paper, compare the colour of the pH strip to the pH colour index provided.
The pH value is (1-14): Surface water colour You can upload a photo of the colour of the water, avoiding reflections from the sun: Hold the camera 40-45 degrees from horizontal towards the water surface. With the sun straight at your back rotate 45 degrees to your left or your right to have the sun diagonally over your left or right shoulder.
To add a photo click here: Looking at the water surface in this direction, the colour of the water is
most similar to Forel-Ule colour number (1-21): Quality control check-list The bottom was visible / the disk reached the bottom while I could still see it.   I reached the end of the tape while I could still see the disk I was not able to keep the disk going down at a straight angle. The estimated distance angle is: degrees from vertical. Go to step 5