Some years ago, a friend and I hiked the southern 30 or so miles of the Ocala Forest in central Florida. It was mid-July, which was of course stupid on both our parts. There’s very little fresh water to filter — the black, brackish stuff sits comfortably at 80 degrees out in the sun.
My friend, Chris, had the previous year hiked the entirety of the Appalachian Trail from north to south. I was an inexperienced hiker stupid enough to go walking through the Florida back country in the middle of July. We were miserable. 24 hours in and I was dehydrated.