please help! leaves are turning yellow

thanks for reading this i need help with my plants. this is my very first time trying to grow. this is the story i bought 3 clones from craigslist "i know i know" first time to try this. well i potted two of them in soil and one is in a hydro drip bucket. i have 4x 54watts T5 lights and also a 1x1 112w red n blue LED. i am using this three nutrients floragrow, floramicro, florabloom. i have several questions to ask. the 3 big plants are clones that i got from craigslist. i have 1 small one it looks fine it was a seedling before.
1. which lighting is best LED or T5
2. can i use a Co2 diffuser in my bucket with hydro? this Co2 is from a planted aquarium i use to have.
3. how high do i need lights to be.
4. i did a DYI 2 litter Co2 with yeast sugar and baking soda.
5. how often do i feed and change water
6. i am using R/O water 5gallon jugs should i pre mix nutrients there.
7. can i feed all my plants the same stuff i have
8. and how do i read a feeding chart i am confused with the process of feeding and what the number mean 1.2.3 2.2.2 please help thanks

hey not to be funny but you might be having a lock out. i am going through this myself at the moment in week 4 of flower. my plants wasn't looking to good when i got them back from a friend, so i watered them few times before i decided to feed them thinking that they were being over fed. when i seen the problem was persistent i checked my run off and to my surprise my ppms was off the charts and my ph was .5 below what is recommended for the flora series. basically all the problems stemmed from salt build up and low ph which locked out certain nutrients.
as of now they have been flushed and are now they're starting to look a little better. i will be keeping a close eye on them for the next week, taking notes, and will let you know how things turn out if this thread is still active.

Over nuted em mate, fresh to de@th is right your plants are suffering from lockout and need flushing.
I always flush with 1litre per gallon of soil of ph'ed water and leave em for about 5 to 7 days or until the soil is nearly dry then repeat again then start adding low level nutes. They should then sort them selfs out.

By no means am i a pro but there are a few things that i have learned and if ur open to them ill share them with you and again this is all info that i have come across rec and it makes senssi {HAha} to me.
Ok #1. mmm... best lights H.I.D. 2part --Mh veg --Then Hps Flwr but i believe u wanter the better o f the two in that case led have been making steady progress and are now resonabilly respected more than flouro but thats what i read i personally stickn with Mh and Hps.
2.dont have a clue
3.close enough to grow far enough not to burn
4.not a ? Next
5. system varied
6. yes
7. NO diff nutes for hydro and soil for hydro yes but u cant acuratley measure the nutrient uptake of each plant if they share a res. if not then u can then adjust ur solution till the Ec gives steady reading in each res.
8. Cant tell without seeing it but gen rule xa-xb-xc .....x=amount of grow per gallon usually mg ---abc= grow \veg\ flower so 5-5-5 would be 5mg nutes fer each part of 3 part system. gen hydro

AGAIN ONLY WHAT IVE READ BUT u can check out my progress so far i think im grasping an understanding of these concepts.
Dont ferget please Show ur gratitude if this was helpful thanks &smoke on brudda