turbidity tube 

       

1.  fill the turbidity to with water

2.  as one person looks through the top of the to the other person slowly let the water out of the tube through the valve at the bottom

3.  as soon as my person look through  the top of the tube Casey the bat black and white Target at the bottom of the tube that says stop and the person letting out the water of the two closest the point

4.  record the height of the water remaining in the tube on your data sheet.