Nute burn? What next?

I think fertigation burn will show up in new growth, at the tips. Discolouration of lower growth simultaneously may indicate deficiency of mobile nutrients, like Nitrogen, Phosphorus, Potassium, Calcium or Magnesium. Such deficiencies may be the result of lock-out as a result of over-watering, or pH inconsistencies, or it may not be present in the substrate. If it were me, I'd probably attempt to let my medium dry out as much as possible (without going too far), then feed with a 50% strength full spectrum fertilizer solution, that contains micro-nutrients. I'm no expert in the use of the fertilizers you've listed, but have witnessed similar issues in the past when using epsom salts without some source of calcium.

Outdoors, in the ground, a feeding schedule of plain water/plain water/fertilizer works best in my experience.........so nutes about every 10 days. Certainly not twice a week or even every 6-7 days............every third irrigation. Lower leaves losing colour at this stage of flowering is normal, but you do seem to have a nitrogen excess and a potassium deficiency. Can't see any evidence of a magnesium deficiency. Not sure how you are going to dial down the sun or un-compress your garden beds! Cannabis can take everything the sun dishes up by the way.

Tips look to have osmotic shock; medium has too many salts. High electrical conductivity influences the electrochemical gradient that drives passive calcium movement. Kinda alters calcium uptake. That and a little too much light, maybe? Just make sure the soil doesn't get too compressed. Try to keep as much oxygen in there as you can. Admire your meticulous work. Look forward to seeing the mass monster!

This looks like low K, but if ph is off or some other nute is amped up too much, could just be inhibited despite planty available. Also, looks like N may be a bit too high -- see some glossy leaves. The high N is more confident and you should reduce that portion without causing much change to the other nutrients (pkcamgs). consider recent behaviour - Has it been consistently provided? if so, make a note to provide less in future from the start. Was it ramped up recently? Even this... problems don't necessarily arise the next day... it can take weeks or months to see ramifications of changing the fertilization mix. Don't assume it is the most recent behaviour that is the cause, but consider the cumulative of all you have done so far, too. Get a leaf symptom chart. google "marijuana leaf symptom chart" and download a high res option so you can zoom in and actually see it well. I like the one with 'jorge cervantes' name on the lower right corner. There are also come good youtube videos of people that purposefully cause a specific deficiency or tox to show the symptoms on a real plant... i look for link but can't find it.. 'rubisco something' did it fairly well. If unfamiliar, the only way to learn is to look at it and learn it. Ask for help in the meantime, but scour over the symptom chart. A good one will explain mobile vs immobile and how that can help eliminate possiblities. Symptoms are not discrete. More than one cause can result in what you see. "Burnt tips" are not always toxicities, etc etc.. Increase your resolution... overall concentration on its own is mostly useless. More important that overall concentration is the ratio of each nutrient element. You can't confidently diagnose without understanding the gist of it. If you stick to teh same products, you'll get familiar with your dosing and this can inform you, but this is not an apples to apples way to understand it. If you buy different products in future, you'll have different dosing and it won't translate. You'll have to re-learn what you already learned before.. wasted effort and time. You can use weighted average by does of the percentages of each nutrient molecule or calculate elemental ppm -- these both will translate (for the most part) when you buy new products. A super anal person stalking me might have a problem with that statement as some forms of particular nutrients do have some slight differences etc etc... but it'll still be infinitely better than relying on dosage, which 100% won't translate unless it's the same exact concentrations across the board. as you refine your formula based on observing plants over time, if you ever buy new products, you can target similar elemental ppm of N,P,K.Ca.Mg,S and significantly reduce trial and error and potentially all trial and error to get it re-callibrated with new products being used. It's good you track this stuff. Data helps. Don't let the haters tell you it isn't useful. Those are the same people that run into the same problem over and over again. Be systematic and grows should be mostly flawless as far as what we control withing 1-3 cycles - maybe more for outdoor/soil growing (more unknowns to adapt to). Evolving what you do or changing products/methods comes with a new learning curve. At this point, I have everything organized, mapped-out, planned for etc etc. Consistency in methods helps bring consistent results. It should not be a stuggle to feed multiple different strains from 1 reservoir. If it is, a little self-reflection on methodology is needed, instead of blaming the plant, which is what most do.