I quit doing the FF but won't make that mistake again. The flies are not around as much now that I've started back. It makes their feathers shiny, firm stools, eat less and clean the bowl where without it fermented, they were wasting/scattering feed. I love it. It looks messy like it would be hard to clean but I use a cat litter scoop to drain it, and with a hose and NO Scrubbing it comes spotless. Seems like the wild birds don't like it either, but I don't really know if that's true. There have been less though for whatever reason.
How many birds are you feeding with the 5 gal bucket? Our flock is gonna triple when I move and will be needing to up the size of my current system.
Right now I'm feeding 6 laying hens and seven 13 week old pullets. The way I do it, not replenishing daily, the 5 gallon bucket last about 5 days, give or take, but I usually don't have it completely full. Then I just refill and add more water to the old slosh. I did leave for vacation once for 10 days so I filled the bucket up. At the time I had 8 laying hens and there was plenty of feed for the caretaker plus several more days after my return. How many will you be feeding?