Thanks for the suggestion. Soon after writing that post I remembered the best guess chart and adjusted the fc to 20 that night and have been working to hold it since. I'm getting really close to being able to see the bottom clearly. Nearly all the junk has been filtered out and I can run the filter nearly all day without needing a backwash. Going to the store tomorrow to pick up more bleach and I'll be sure to keep the fc up high enough that it won't ever dip below 20.