Taken a few pics of one of the affected leaves. Th...

hiya there, you almost got it actually it's phosphorous deficiency, you can tell by the strange coloring of the leaves . plain water wont really harm the leaves like that, even in the light, after all it does rain on plants even when it becomes sunny afterwards, you know ? basically you've got P def. so just up the bloom nutes, cut out the veg nutes, and or add some PK, and stay on top all that PH, and make sure you're watering at around 21°C. Hope this helps ! 🚀

Wow, that is some cocktail you have there. Anyway, that's over feeding, I usually get that same kind of effect when overdo the cal/mag, I use 0.7 ml per liter and when I go over that I usually get that crispy leaves with interveinal grey patches. Get an EC / PPM meter and check how much you are feeding. For now feed water only. Are you really using 1.8 ml/lt of calmag? That's way too much.