Please Help!, Babies are dying slowly, Help Diagnose,Yellowing Tips...PH?

************Look closely****************
AK47, Critical Mass, California HASHPLANT, and Some GD Purp.
all have the same symptoms

System-Aeroflo
Lighting-2-600W HPS COOLTUBE (aircooled)
Ventilation- 2 elicent cent. fans 450 and 850 CFM
70-76F
45-60% humidity
67-69F res temps
Circulating fan
currently at 100PPM never went higher than 200PPM

Hello this is my first post but I've grown all types of different methods. Currently my setup is 2 aeroflo-like systems with 28 sites total under 600HPS aircooled by 450CFM Intake and exhausted with a 850 cfm, the room is circulated by 18" fan. My nutes are:
3-part general hydro (grow,micro,bloom)
Cal-Mag Plus
Liquid Karma
Hygrozyme
I started off with .2 EC, the plants were slighty yellowing so I upped the EC to .4 and they continued to yellow at the tips, one of my established clones then started dying off(yellowing) . Ive tried to keep the PH between 5.6-6.3 it has stayed toward 6.0-6.2, seems to be very hard to keep below 6.0. The pump is run on for 1 min and off for 5 mins. each plants' roots are going nutz like they do in aero but above seems shakey. The temps in the rez stay around 67-68, and the room temps stay around 75F. ranges from 68-79. the plants are about 18" from the plants. EVERYTHING SEEMS PERFECT! its very frustrating, any Ideas from someone experienced. Ive read that after clone its cool to give like anywhere from 800-1500 PPM of nutes. Ive never went above 200 and now its at 100PPM. Am I just a pussy and I should give em some nutes. Could they really be deficient? THANKS FOR ANY RESPONSE.

yes feed them. Low ppms if feeding evey watering but higher if not . looks to me they need some food. Ph is there so hmmmmmm

What do you think I should start with ???PPM.
Also, will yellowing leaves ever get green again or will just the new growth be green?

i would trim the dying leaves because this could be a disease and if you do not trim it could spread to whole crop. Also what is the ph of you water after nutes are added the water could be to alkaline in areoponic system you dont really want ph above 6.2-6.3 and not below 5.5, also it kind of looks like a bad magnesium defficiency

Concur with the diagnoses' but would like to emphasize -
Get that PH down ASAP... Like yesterday.
Your plants aren't clones anymore, and to sustain them - THEY NEED FOOD!

Here is a great nute schedule from a great grower named hererisssh on another forum I belong to.

Basic Veg Formula (1 Gallon):
Botanicare Cal-Mag + 5 ml (only if using RO filtered or rain water) *which in this system - you should be using RO water***
Cannazym 9 ml (Prozyme, Sensisym, Nitrozym, Multizyme are similar) *hygrozym here*
Botanicare Liquid Karma 12 ml
Botanicare Pure Blend Pro Grow 8 ml
PH Adjust To 5.5

I have followed his journals - and this guy pulls down 3-8 oz of DANK per plant... his schedule is legit.

Your babies will be fine, but get that PH to them - and give them some munchies!!!
Think about it this way - an 8 year old child is going to die quickly if he was still just getting breast milk.

Thanks for the input, I just gave one of the two system 450PPM and left the other on flush we'll see what happens. Appreciate the input

Good deal bro - post results in a day or 2 so we can see your progress - happy growing.

- Big D