why did you use big bloom, those plants are still vegging, you should be using the grow big only! also the brown tips is usually nute burn. for a 1st feeding you should have done as i said, 1 tsp(5ml) of grow big per gal of water then ph'd to 6.0-6.5 with ph up. you gave 10ml of grow big and also big bloom thats too much! also i hope when you said 2T of grow big you didn't mean to tablespoons because 2 tablespoons would be about 6 times to much ferts for a 1st feeding even without the big bloom which isn't necessary in veg anyway. good luck and remember start slow with ferts then work up gradually!