Alien OG (F:43) -- P? pH? Everything's fine?

First grow, looking for any insight/advice!

• Alien OG
• day 43 of flower
• soil medium w/ perlite + vermicast
• feeding GH's organic line
• "micro-grow" in a spacebucket

Lately some lower fan leaves have been yellowing- I leave them on until they take very little effort to remove and pull right off without a snap. I've figured this was the plant using up what energy was left in those leaves, then clearing out the canopy a bit to help light reach lower buds. However, while watering away from the lights today, I realized that even some of the higher leaves are losing their colour, and am a little concerned that the plant might not be in tip-top shape.

A bit of a reddened stem/vein on the leaves has got me wondering if perhaps this is a P deficiency? I encountered something similar a few weeks ago while flipping from veg, and found that increased pH controlling seemed to fix things up. So I did my runoff test while watering and WTFFFFFF!

Here's my past few waterings:
03/05 : 6.20 in, 6.7 out (feeding)
03/09 : 6.20 in, 7.0 out
03/12 : 6.25 in, 7.0 out
03/16 : 6.30 in, 6.7 out (feeding)
03/18 : 6.70 in, 7.0 out
03/22 : 6.40 in, 7.5 out

What could possibly have thrown the soil acidity so out of whack? One poorly balanced liter of water on the 18th? I immediately followed today's watering (pH 6.4) with a second one of the same volume, pH'd down to 5.5, hoping to balance things out. The runoff again measured around 7.5

I'm really uncertain here because to my noobie senses, the buds look and smell spectacular, but the rest of the plant is far from the lush green that I got used to during veg stage. I also wonder if a seasoned expert might not look at this plant and suggest 'lollipop'-ing much of the lower growth off. At this point, is it too late to attempt monster cropping?






^03/14 - 03/21

Like I said at the top, any advice or feedback would be appreciated. Maybe I'm over-worrying and this is just what a plant in flowering looks like? Maybe it's in its death throes and needs immediate response? Let me know what you think

Thanks!

Based on picture showing leaf tip clawing and poor color, I'll guess nutrient antagonism (lock out) from over feeding. Good luck!

Iron deficiency Chlorisis by the looks of it. I assume this has been going on awhile though.
Will only effect top growth but like I said, I assume this has been an issue for awhile.
Salts, pH ?
Definilty out of whack with your nutrients, but probably due to pH.

Could be sulfur as well which may effect both new and old. Confusing one for sure.

Thanks so much for your diagnoses, I suspect overfeeding could be accurate. I'm using the General Organics line, and have been using their recommended amounts - guessing I could probably make do with half strength. Have always used a feed/water/water schedule, hoping that would help keep everything in balance...

More importantly - how do I get in front of this issue to maximize potential throughout the rest of flowering? Lockout means it's time for a flush? If I've been balancing everything to ~6.2/6.4 and am consistently getting runoff of pH 7.0+, should I be balancing waterings down under 6.0?

Note that I unfortunately do not own a ppm meter, but let me know if there's any other tests that I can run or photos that I can take to help suss this out.

should I be balancing waterings down under 6.0?
Yep