I would stake my reputation that your pond is not predominated by a diatom bloom. Algae / phytoplankton blooms come and go (wax and wane) due to nutrient variability and fluctuations; yours appear to be a persistent problem. Brown hue algae blooms normally do not have the color of your pond. Your color has a mud -dirt color. I can microscopically look at your water and verify the type of particulates. My guess at this point is detritus, silt, and clay is the main cause. Your current problem is not an algae scum type of problem that is referred to in the Kentucky booklet you reference above. You do not have a scum. You have particulates that are present in the entire water column, top to bottom,