Please help me diagnose my problem!

So here are my problems..

1. Is that normal for two plants of the same strain started at the same time to have major growth differences?
2. New leaf sets are coming in twisted as you can see in the pics. What could be causing this
3. Is the pale green in the middle of current and new leaf sets nutrient burn or nutrient deficiency?

The strain is bubblelicious Auto Fem from nirvana
Running 18\6 light sched under a 400w MH
Ph in water is checked daily and is kept in a range between 5.5 and 5.8
I have one 160cfm fan for exhaust and another to air cool my hood
I also have an ionic breeze type air filter in the tent and well as ac being vented in through the bottom to keep temps in the 70's
Room temp stays between 75 - 79 degrees (last week my ac messed up so the temp was in the low 80's for about 3 days.)
Both plants were started at the same time about 6 weeks ago (so much for auto i guess?)
Using Bubble Buckets with clay pellets and rockwool.

Pics are below. Thanks for your help in advance!!

sorry about the bump but i could really use some help

Looks like you could use a lil nitrogen but other than that they look fine.

And yes two different seeds of the same genes can grow totally different. One is expressing one phenotype of its parents and the the other one is expressing some thing different. Lets look at it this way.....your parents have three boys, your mom has blue eyes and your dad brown. Two of your brothers have blue eyes and the other one brown. Just because they come from the same parents doesnt mean the will all be idenical. Get what im sayin?

makes perfect sense, i was worried something might be wrong because of the progress of her sister. I'm going to change the res water tomorrow so i'll give it a good flush and add a little extra nitrogen this time around. I wasn't sure if it was nute burn or not enough nutes but i guess that answers my question haha thanks dirt!