Need help diagnosing potential overfeeding

he did say "he thinks" the water was adjust to 6.5 but you and everyone else thats adjust tap water with acid knows that litteraly a few drops in tap will swing your ph a crap load depending on the brands and stuff.. my money is still on him not knowing the exact PH and having acidic feeds that have just built up to the point the plants responding.

I know the pH is definitely not too acidic, if anything it's too high. I have a test kit it's just impossible to get it bang on with the colour comparison. My tap water comes out around 8.0 I'm not sure why. Grotek ph up/down if that matters. The plant I fed yesterday doesn't seem to have gotten better or worse yet. Temps got down to 18c last night, could large variations be the cause of the leaf folding? Here's a pic of weird brown spots on a leaf near the top of the most affected plant.

Give it some calcium and epsom salts, my ww is 5 weeks, no purpling, all green