please help before its too late

hey there so i am in my 6th week of veg indoor. im using a roots organics soil mixture and have the roots excelurator, GH Flora 3 part. i have 3 plants that are purple dragon, and 3 white berry. the 3 purple dragon went from rockwool to a 20 oz. cup, to a 4 gal. pot. Now the 3 white berry went from cup, to half gal pot, to 4 gal. With the white berry i did add pearlite to the soil for better drainage. all 6 of my plants have not been given nutrients for 6 weeks. When i watered them last week i checked the ppm of the runoff water from the white berry and it was at almost 3000. so i flushed 2 of my white berry with 3 times the vol of soil and got the ppm down to 550. All of the plants were looking great up till 2 days ago. i did an even part blend of the GH nutrients, i checked the ph and it was at 6.2, and the ppm was just under 300. now the town plants that i flushed have picked up a lighter almost pail green toward the top of the plants and a couple leaves have white tips that are curling up. so how do i fix this problem, and do i have the right stuff to fix it with?
Please gimme a hollar soon!
Thank you

Without pic's its hard to help. But it sound's like you have a Nitrogen def. But again its hard to tell without pic's...

You need a bigger pot. if your not going to be feeding them use good soil. like happy frog or oceans forest

I agree with Mrstickyscissors. I use COCO Pro and my ladys love it. Its a medium made from coconut coir. And if your going to repot, then get some perlight to mix in with it and some clay pellets for the bottom of the pot. This help's with air and moisture...

Dan