Browning plants

First of all, this is my first post and I think this site is great and I love the community.

My (veg) grow setup:
-4 23W 6500K CFLs (I will be adding 2-4 more CFLs once they come in)
-Soil is a 50/50 mix of Fox Farm Ocean Forest and Just Right Xtra
-Fans are constantly on keeping the temperature between 75-80F
-Fox Farm Grow Big nutrients
-Water with pH 6.5

Plants History:
-6 plants: 4 weeks old from seed
-Didn't use nutrients for the first 2 weeks
-3rd week started half recommended nutrients
-Transplanted 4 of the 6 strongest plants from party cups to 1 gallon smart pots
-4th week started full nutrients

The problem is that in the past 4-5 days the leaves have been starting to turn brown. Most of the problem is on the weaker party cup plants so I flushed those plants and noticed that when using pH 6.5 water, the runoff was 7-7.2 (using brand new Hanna pH meter). The leaves on my transplanted plants are starting to show the same problems. I have looked at a few guides about sick plants and am not sure if I am burning them or if there is a deficiency. I thought it would be helpful to gather some input from more experienced growers.

Pictures:


Thanks for the help

Just seeing if anyone is able to give me some help...

I forgot to mention the light cycle is 18/6.

Looks like it might be a little nute burn. Might wanna slack off the nutes entirely for a couple of weeks and see if it clears up.

Sounds like a good plan. I'll give that a shot. Thanks for the help.

pic 2 looks like someting was eating it.

re-pot them. your strangling them in those tiny cups and that velvet thing.