leaves curling down?

growdiaries.com/journal/what-is-phosphorus-deficiency-and-how-to-fix-it Here's a link to compare for phosphorus deficiency

You definitely have a phosphorus deficiency the purple is a great indicator of such if you Google it, you can compare the colors, First, balance pH (Hydro: 5.8, Soil 6.0 - 6.9) or re-apply nutrient mix if necessary. Organic Solutions: • Bat Guano • Bone Meal • Crab Shell • Crab Meal Inorganic Solutions: • PK Boost Supplements • Phosphoric Acid (Soluble Phosphorus however raises pH quite a bit)

Nitrogen toxicity causes leaf tips to curl down and claw. Also Shiney leather like leaves. Plus the deep dark green is most obvious sign. It is not phosphorus related. The amount of green in your leaves tells how much nitrogen is in the plant. This was one if the first things I learned 3 years and some change ago when I had same issue.

You have nitrogen toxicity. Reduce the amount of nitrogen in your feed to half what it is. Do not starve the plant of other nutrition it is using by going to no feed. Just cut way back on whatever your feeding that has nitrogen in it. Flowering npk basic ratio is 1-2-3. Nice grow you have going. 👍🏻

You have a Phosphorus deficiency which is why you have purple leaves and your temperature is maybe to low for your plants. I'd also have a good luck for any male parts in your area but you really need to get the environment better before you have more issues with your girls happy growing