Muddy water caused by suspended clay particles can sometimes be corrected by spreading broken bales of high quality hay or barley straw in the water around the shoreline. Acids formed during plant decay can cause clay particles to settle.
Approximately two bales of hay per surface acre should clear the water. Do not use too many bales and do not use uncured or fresh cut vegetation. Either mistake may cause a fish kill. To determine if this method may work, add two tablespoons of vinegar to your water sample. If it clears overnight, use of bales will probably work.
https://ag.purdue.edu/agecon/Documents/FAQ11.pdf
