Autoflower Blue Dream

This week had to raise my lights. I didn't LST correctly and the main stem is growing tall on both plants. Many buds sites. I counted around 16. This week I tested the water runoff. TDS=1950 PH=6.2 The soil nutrients are still feeding the plant from what I gather. I have been adding Black Strap Molasses to the watering once a week. I have added any other nutrients. Not sure how long I will be in flowering. I suspect through the first week in July. 👌 On day 56-57 Im starting to see yellowing of leaves. Im not sure what is happening here. Comments? 😫Boy, did I screw up. My PH at tap is not 9.0 its 7.5 I did not calibrate the new PH meter I bought at the start of my grow. I thought it was good to go. So realistically, for the last two months, I have been giving my plants 4.5 - 4.8 tap water after adjusting my PH. So will feeding plants acidic water stunt growth or cause nutrients lockout? I measured my TDS and PH soil runoff a week ago: 1900 @ 6.3PH. Its more likely around 4.8 PH. Thoughts? My plants look ok, but they do look like the are a couple weeks behind schedule.