Disk reappearance Wind the spindle down until the Secchi disk disappears from sight. Wind it up again until the disk re-appears.
Note that the disk should be lowered straight down rather than at an angle. Adjust the weight if needed.
Record the length of the tape from the handheld device. The distance from the device to the water surface will be automatically subtracted.
Distance to re-appearance: cm Go to step 3