Help my babies need attention!

Im a newbie at this, this is my second grow.
400 watt hps and a 250 MH for vegging and two 400 watt hps for flower. Problem that i cant solve is that in late vegging my plants begin to turn yellow starting at the lower fan leaves and curl up. They drop off as quick as i can pick them up.

I've been using earth juice grow which is 2-1-1 for the first batch and for the last i have been cycling earth juice grow and alaska fish emulsion which is 5-1-1 every other week for vegging, and alaska morbloom 0-10-10 for flowering.

I water everyday as the soil feels dry and fertilize once a week- Im using fox farm planting mix and in two plants i also added perilite.
What is going on? Am i doing wrong? Why yellowing leaves? They are all falling off again on 3 different plants?
Could they be root bound?
My plants are 2 1/2 to 3 feet tall in 3 gallon pots?
I tried flushing with no effect?
PH is 7.2
they are always perfectly healthy til bout 2 feet tall in vegging. I have other pretties started and i dont wanna fail with them too Sad stnr

how can i post a pic? yup im a stnr too

ok there i figured out how to post pics, look up, then is that long story worth reading? Im stressed HELP ME

Try re potting in a larger pot and stop watering every day,that looks like a pretty tall plant there and I usually go by 1 gallon of soil to every foot of plant but since you have been watering so much you might have monster roots just give it a try what can it hurt?

do you adjust the pH for the fish fert? It is very acidic and could be causing lockout of other nutrients. In what proportions do you add the fish fert?

I use one tblspoon per gallon of fish fert once a week. I just purchased a ph tester and it appears to be 7.2 which i believe is good. I am also transplanting to bigger pots-5 gal. Looks like a huge root system.
Could feeding them a 2-1-1 fertilizer once a week be too little nitrogen? Has anyone had success using such a light fertilizer? I have heard people using stuff like 35-20-20