2.9mL x 1.6mW x 2.0mH grow tent, 2 x 600w hps running in cool tube, carbon filter extraction fan, isolation fan, 6 plants in double pots all link together running back to reservoir, drip feed system, re-circulation water pump and air pump in resi, using coco for grow medium, nuts- nf coco A&B, mostabud and will be using add bud for flowering. Have done a lot of searchers and read a lot off the internet before deciding to post thread. But because this is my first grow i don't really know how to diagnose whats happening with my plants. Today is the 3rd week of veg, toped the plants about 4 days ago, ppms are at 800 and ph at 5.8, lights are sitting about 1 foot from top of plants, have had some hot days so temp has been between 26c to 33c, lights are coming on at 6am, feeding 4 times a day 2mins at 6:15am 1min at 10:45am 1min 3:10pm 2mins at 7:18pm, pump flow 45secs = 500ml. Edge of leaves are curling upwards. Please have a look at pics and let me know what you think. All help will be much appreciated. thank you for your time.