Reasons for the leaves to claw down so bad? ( I think its the heat? )
Ph is balanced
Biobizz light mix soil
Watering every other day with 300ml ( 0.5 ml biogrow, 0.5 bioheaven, 0.5 alg a mig, 0.5 root juice) week 3 day 20 from first leaves.
You don't have a diary for this grow but I would tend to guess (and that's all you're going to get are guesses without a diary) that you're dealing with some nitrogen toxicity... OR overwatering...
Good luck