Hosmer Lake is good in all areas of the lake from the lower lake near the boat ramp, to the channels and up in the upper lake. There has been a strong hatch of callibaetis here in the afternoon. Damsels are also improving and will be a key food source for quite a while as nymphs and as adults. I’ve been on Hosmer a lot this past month and leeches are a constant food I pull out on the throat pump, from big black leeches to smaller olive ones it is apparent that the fish want to eat leeches now. Small olive scuds and callibaetis have frequently been in that mix too. 
The water is low, I think at least a foot or more lower here than the last couple of years. It is noticeable and running an indicator means doing it really close to the flies in the upper lake especially. Stripping flies is a mess in a lot of spots, but not all. What you’ll notice and it might go away is a fine algae filament that gets stuck to your fly really easily because it is on the bottom on many places throughout the lake and channel