Yellowing on lower, older leaves. Starts with cris...

Hey there the plants really made an amazing come back from last week. Well done. The only other thing I could've thought possible would've been a magnesium deficiency, which will show the burnt tips similar to a burn but will also yellow between the veins of the plant. From most nutrient schedules I've seen, many of them list doing a flush at the end of the vegetative cycle, and again at the end of the flowering cycle. They really do look great this week, keep up the amazing progress. ☘️✌️

What you are experiencing is nutrient lockout dues to excess feeding, looks like a textbook nutrient lockout due potassium excess, 2.08 EC (1040 PPM) is high even for flowering stage. Give it a good flush and stop all feeding. With a 16 liter pot, you don't need additional nutes for quite a while. Don't add nutrients unless you see signs of deficiencies, a slight deficiency doesn't impair grow or flowering, but a nute burn is disastrous. Also 2 liter of water every day? are you sure? that amount of water should last you 5 or 7 days.

Hey my friend, you have too much nutrients in your water, give her a good flush, then give her two days and she 'll be ok...

This looks like a textbook zinc deficiency. Zinc deficiency is usually a symptom of a greater problem. It looks like you are using a lot of nutes, I would cut that out for a week. Causes: Over watering is usually the main reason or lockout due to over nutrient use like potassium Root problems such as bugs or rot Not using the proper or quality nutrients when growing RO water is missing vital trace elements with a PPM of 0 High PH soil (check your soil ph values )