My replacement float arrived today, & I finally got this figured out. The float is styrofoam; I assumed it was a piece of molded plastic. Duh.... After seeing the replacement, I looked through the bin holding my recycled packing materials, and there was the original float. I had thought it was just part of the box's packing & tossed it. Good thing I keep such stuff, but I feel darn silly now... & I also now have 2 floats....