Overwatering? Heat damage? nute deficiency? not enough nutes???? first real grow!

hey how ya goin! im having some huge probs wit my grow! thought u could help me out some? the leaves are curling upwards and are drying out real badly.plants: 7age: 20 days oldlights: 600wt hps at about 15 inches away (now) before like 12inches fans: two exhaust one right above light the other a bit higher both putting hot air in the room, two other fans one outside the room pushing air in the other inside pushing it into the grow room and ocilating out of the room to cool it down.temp: always around 25 used to be at 30 but that was a week ago. RH always at 20% added three bowls of water todaynutes: dutch fest hydro grow A&B originaly using root hormones for first week or sosoil: originaly organic compost only the soil around roots was perfect ph but the outer soil was around 8 to 9 alkalinity, i repotted today with premium potting mix at a ph of 7 and perlitewatering; i thought i was over watering so didnt water for 3 days today when i repotted i watered about 3 litres with a mix of 10ml each a&b of nutesbelow some photos from 3 days agohttps://www.rollitup.org/general-marijuana-growing/584142-over-watering.html would love some advice please hit me uptk

First, it's a little difficult reading what you wrote since there are no paragraphs, etc20% humidity is too low. In veg you should be aiming for about 60% humidity and in flower about 50%. You can purchase a humidifier or if you have no money for such you can rig something like a t shirt with the tail of the shirt in a bucket of water and the rest of the shirt spread in front of a fan...your own diy swamp cooler.

Happy turkey day! Keep an eye on humidity levels there important obove post is good to go by. If leaves are curling upward it can signal magnesium is low do you have a meter? Also if your going by your nute bottle and what is says on the back of bottle that's usually for a big plant u know a mature one. The pic won't come up but if u can post another it'll help a lot with the diagnoses

Also is your soil amended? If you are using compost/potting soil, it probably has nutrients already in the soil and by adding more through watering you may be burning your plants.

Light is way too close. 18" minimum and maybe farther away. Put your hand where the plants are under the light for 30 seconds. Is it warm or hot? If it is even really warm it is probably too close.