i can see a bit of magnesium deficiency on the plant on the left (yellowing but with dark green veins) and calcium def is random brown spots, but it could also just be the plant drawing nutrients from the leaves.
have you got your lights at 100% ? could be light burn

Thanks @carlosescobar. I looked into calcium deficiency and I thought that was probably it, but the problem is still progressing. I thought I had it figured out as a calcium deficiency caused by low ph at the roots. I started feeding with ph around 6.35 every day (coco) but I hadn’t been testing the runoff until a day or two ago and it was about 5.85, which supported the idea of low root ph causing calcium deficiency. So I flushed with the regular nutes at ph 6.35 until I had the runoff to 6.2. I’ve been feeding the recommended dose of GH Calimagic throughout the grow. I also turned the light above it down to 80% and raised it a little. The problem may have slowed down, but the discoloration and crispness is still spreading. Would that be to be expected even if I’ve solved the problem, or do I have something else going on? If not calcium def, I have no idea where to go next. Any ideas?

I just noticed this morning that some of the leaves lower down the canopy have some distinct yellow tips. Could the damage in the photos above be from overfeeding?
I just have no clue how to fix this. I could really use some help with this.

What's the temp and rh been like? Calcium can be sensitive to those too. From the pics I'm not totally convinced it's Cal tho..If it were my grow I would dial back the nutes a little and aim for 6 ph. I think maybe they're a little over fed and that can actually block the calcium. The rest of the plants look super healthy and happy despite some nute burn. Sometimes it's as simple as adjusting the fans. What's needed for airflow when the plants are small changes a lot when the space is that full. My fans are frequently at a different place and setting and the end of a grow compared to where they started.

More plants get killed by love than by neglect

You might try backing your light off just a tad while you are trying to get a handle on things.

Thanks @Grownsince95. Daytime temps around 75; nighttime about 68. RH stays 45-50%.
@BearWater I backed down the light above the affected plant to about 80% a few days ago. PPFD around affected leaves is 550-650. Seems like that should be okay for a struggling plant?
One fan on oscillate underneath canopy, the one above on oscillate. Exhaust fan up top turned up fairly high. I’m keeping a close eye on the buds and lower leaves, but I haven’t seen any wet leaves or buds.
I’ll definitely dial back the nutes today.
I’m just starting week eight after flip. I pick off a fan leaf or two when I see they’re blocking buds. Maybe I should defoliate a little more? Someone recommended I defoliate a little heavier about this time in flowering, but it doesn’t seem like I should trim a sick plant?

I defoliate the bottom and middle crap all the way through the grow. More for airflow than light.

Anything Nute at this stage (excess for deficiency is out of my experience level) but I think lowering the light intensity a bit may help (may) lol. I take fan leaves that block under nodes : )

What is the PH of your water with nutes? Might be a lock out rather than a deficiency due to lack of calcium and magnessium in the soil. Youre using a supplement that is precisely to avoid calmag deficiencies and floramicro also has calmag so I highly doubt the ammount isnt there, its something else.

Also this is the official chart for when youre using calimagic. There's no chart for just tripart and calimagic but it should be able to be absorved even though the low nitrogen makes me wonder if it works with the other supplements for optimal intake, because its sold as the "pro performace pack".

Floralicious plus is 2-0,8-0,02 but I dont know if that nitrogen is suposed to help with calcium. I would think so since extra nitrogen during flower after the stretch doesnt have as much use, its the first time that I see a flower booster or nutrient that has twice as much nitrogen as anything else since there should be plenty in the base NPK. I dont know, its tricky, only they know if they made those two to work together but there's no chart that cotains calimagic without those other 2 supplements. The other one is just tripart without supplements and then theres another one with even more supplements.

BearWater said:

Anything Nute at this stage (excess for deficiency is out of my experience level) but I think lowering the light intensity a bit may help (may) lol. I take fan leaves that block under nodes : )

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you are not giving too much in the way of nutrients otherwise you would have tip burn , coco apparently holds onto a lot of calcium , and calcium competes for uptake on the roots with other nutrients, . i did this a few weeks ago and as soon as i added calmag it cleared up immediatly,

The thing is, he is already using calmag and a base that also comes with calcium and magnessium. Even the hard water version comes with calcium and magnessium (there's the soft water micro version that comes with even more). Which one are you using? And what type of water and PH?

carlosescobar said:

you are not giving too much in the way of nutrients otherwise you would have tip burn , coco apparently holds onto a lot of calcium , and calcium competes for uptake on the roots with other nutrients, . i did this a few weeks ago and as soon as i added calmag it cleared up immediatly,

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Thats what I was wondering when he said he was going to lower nute dosages, I never said to do that and didnt want his medium to get more thrown outta whack than it might already be by messing with the nutes. In my opinion at this point in his grow it’s probably a lack of or some lock out? (Is that accurate?) : )

great to hear you were able to clear your problem up!

Eledin said:

The thing is, he is already using calmag and a base that also comes with calcium and magnessium. Even the hard water version comes with calcium and magnessium (there's the soft water micro version that comes with even more). Which one are you using? And what type of water and PH?

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Exactly! I'm my experience Ca is usually abundant when feeding "by the book" but because the plant cannot move it around like other nutrients, it has to be available in the root zone every feeding. That's why cal/mag deficiencies show up at the top/new growth. Other movable nutrients get sucked up from older, lower leaves when the root zone stops providing them and start showing from the bottom usually.
So if you know you're feeding it enough calcium, environmental factors can get in the way of absorption. Also too much Potassium can block Calcium so that's why my first instinct was to lower the feed.

Eledin said:

Also this is the official chart for when youre using calimagic. There's no chart for just tripart and calimagic but it should be able to be absorved even though the low nitrogen makes me wonder if it works with the other supplements for optimal intake, because its sold as the "pro performace pack".

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I had not seen that official GH Trio chart and now I'm a bit confused because that chart doesn't seem to even fit what's on the bottles of the Trio at all. For me in week seven, the bottle says Micro 10ml/gal, Grow 5ml/gal, Bloom 15ml/gal and Calimagic just says 1 ml/l. However, I've actually been religiously following this chart I found on GWE since it seems to have been working so well:
general hydroponics flora trio custom cannabis nutrient schedule by GrowWeedEa">

I'm at the end of week 11 in this chart and the only thing I've done differently is that I've been giving them CaliMagic all week, even though it says to discontinue it. I did that because the issue started showing up around the start of the week (I think I actually omitted it for one or two days).

Eledin said:

What is the PH of your water with nutes? Might be a lock out rather than a deficiency due to lack of calcium and magnessium in the soil. Youre using a supplement that is precisely to avoid calmag deficiencies and floramicro also has calmag so I highly doubt the ammount isnt there, its something else.

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Prior to this week, I had been allowing the ph to drift up by .2 to 6.4 and then down by .2 to 5.6, which in my thinking would allow the plant to uptake any nutrient it needed while not causing too much of a change at any time. I did this throughout the grow. When the issue first started happening, I was on the way back up to about 6.0, which means I had fed below 6.0 for about four days. I'll admit I'm a little OCD, but I saw a chart where certain nutrients could only be absorbed at certain ph's. For the last four or five days I've been feeding around 6.3-6.4 thinking the low ph had locked out the nitrogen. When I finally tested the runoff a few days ago, it was 5.85, so I thought maybe I had the problem solved and could remedy it by feeding higher ph's, which I've been doing until the runoff has come up to 6.2, but the decay is still spreading.

carlosescobar said:

you are not giving too much in the way of nutrients otherwise you would have tip burn , coco apparently holds onto a lot of calcium , and calcium competes for uptake on the roots with other nutrients, . i did this a few weeks ago and as soon as i added calmag it cleared up immediatly

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I actually having a little tip burn as of this morning. Your photo looks like all the photos I've seen of calcium deficiency, but mine looked a little different to start with. This is how it started a week ago:

See how it started in the center of the leaves in one splotch and then spread out? Not like the spots of brown caused by calcium def I see in your pic and so many others. This has made it really difficult to pin down for me.

Eledin said:

The thing is, he is already using calmag and a base that also comes with calcium and magnessium. Even the hard water version comes with calcium and magnessium (there's the soft water micro version that comes with even more). Which one are you using? And what type of water and PH?

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I am using well water that is moderately hard with a ph of about 7.6. I'm just using the standard Trio--it doesn't mention water type or hardness. I'm using the GH ph Down.

Grownsince95 said:

So if you know you're feeding it enough calcium, environmental factors can get in the way of absorption.

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I'm certain I'm giving them enough calcium, probably way more than they need, but I can't figure out what other nutrient or environmental factors to adjust--and that's even if it is calcium def.

I have to thank all of you. I'm an English and Creative Writing graduate so it is deeply ingrained in me to be very thorough and specific, even at the cost of wordiness. I am well used to seeing people's eyes glaze over at my ramblings--as I'm sure some of yours are now too.

Honestly, that far along into flower and just barely 10% of plants affected I would just move on and make a note in the book. Looking again at the pics you have that really deep army green which means there's plenty of nitrogen and potassium. Maybe too much potassium, which will fuck with the calcium uptake

Grownsince95 said:

Honestly, that far along into flower and just barely 10% of plants affected I would just move on and make a note in the book. Looking again at the pics you have that really deep army green which means there's plenty of nitrogen and potassium. Maybe too much potassium, which will fuck with the calcium uptake

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Thanks. I'm hoping if I can't figure it out, I can at least slow it down enough so I can coast till the end. It's a Grape Ape fem, and data sheet says 7-9 weeks flower. I'm starting week 8 and it looks like I have a long way to go to me, but this is my first grow. The 50/50 hybrid Larry OG beside it is quite a bit farther along and its data sheet says 8-10 weeks. I guess I won't be able to harvest them together like I hoped.
Here is the pic this afternoon of the burnt tips. They just came on today and only seem to be on those few leaves.

The photo is making those tips look brown, but they are actually bright yellow.

Are the upper tips affected in particuler while the rest of the nodes seem to be better or with no yellow tips? If so the light was too close.