I'd say head to Wally World or a hydro store and get either strips or a meter asap.
My suggestion would be check the water before using it again and if it's fine you know it's the peat.
To be honest the brown spots came after I watered with Epsom. I also watered back to back and showing signs of over watering.
I screwed the pooch and didn't follow my own advice. I should have left them be.
I'm going to get some today. I've got pine needles and what not in my rain catch.
Even with the problem, whatever it is, they are trucking right along.
Actually, can't be the rain catch. I water my garden with it and its fine.
Got to be the peat. How would I correct that without digging them up? I'm the one telling everyone you don't need a pH meter with soil, especially with organics.