It looks like you're pushing a few toxicities anyway so it may be a good time to give them straight water for a week or so, both copper and boron are hard to remedy on their own because you need to add those particular elements, and not any others. And unless you have a crazy nutrient system that has all your elements separate, you're nutrients come bundled so it's better to flush a bit to lower the entire nutrient levels in your media and start with a fresh/complete/balanced nutrient solution in a week. At that point your plants will have all the nutrients they need without overdosing them on everything they don't right now.
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