Im gonna agree with farmer sorry I haven't responded I think your seeing old issues farmer saying think in weeks is a good plan its not gonna heal over night the unhealthy ones damage might have been worse than you originally thought sometimes they will continue to worsen even after conditions are fixed up to acceptable and only time will show you if its gonna turn it around but on the same note being new your gonna have problems and alot of work will be needed on problem diagnosis even for all the wizards out there!! So you don't wanna assume its an old problem and let it go until you find out it was a new problem n ur plants dead!! I think your perfect its good to be a little paranoid, a little extra tlc will only help teach you jist as long as you don't love it to death, I'd keep watching the sick one for new problems spots marks etc stick with regular watering letting your soil dry 1/3 of the depth of the pot between waterings and see how they look in a few more days.. and in soil 5.8 is low you wanna be around 6.5 and your water for watering should be no more than a few points off from your run off as to not shock the plants...