I perfer Earth Juice myself. 80ppm Earth Juice Grow and 20ppm Maxicrop flakes. You can go up to 300ppm and not worry about buring tips however plants do not need that much. Look mostly sativa. PPP maybe?
They look good to me, the tips can be from a number of things. Most likely just a tab much nutes, don't worry.........mine have and do the same things lots of times. Just keep up the good work and speak words of encouragement to them every day.....and I do pet my sweaty plants every morning and afternoon.....lol