1. Waterbase
2. Clean without using chemicals. If dock has treatment on it you will have to remove the pier out of the water and clean and treat it on shore.
3. When applying wood treatment you have to have something underneath the dock to prevent the treatment from going into the water.
4. Don't spray the dock apply treatment with a painters pad.
5. Use cold water to clean.
6. Call the DNR and have them look at the dock, get written authoration for doing the project.
Charlie