I have also experienced this (the joint part) ....... in my considered medical opinion (which is
worthless since I am an engineer by trade) taking fluid off down to a dry weight is not an exact science and I have speculated that if enough is taken off my body pulls some of the synovial fluid out of my knees.
But it is probably just sitting there for hours.......
I dialyze right after work at home so I also go to bed with an hour or two. But, although a newbie, I sleep better since I started. And need less sleep.
sp mod Cas