Your water parameters look great!
I asked Marvin Emmerson, whose family developed the Emmerson strain of trout in Ava, Mo. to look at your pics and give his opinion. IIRC, he said PH was not much of an issue with trout. I also doubt your inflow would change the PH fast enough to cause any stress---Not much different than runoff into a natural stream.
Try your antibiotics. I'd still add some salt--it's cheap and is a stress reducer.
