Burning of leaves + yellowing - fully sick in the worst way possible

Hey team,

My girls are 8 weeks in, still in veg.

I've had my ups and downs with them but they're looking the worst they have.

Had a N deficiency, that cleared up for a couple weeks, now my leaves are yellowing and looking as if they've got nute burn. If I add more nutes then they get more burnt, but if i don't add any then the leave die.. Quite the predicament.

ALL of my old leaves die, none of them get very big. new growth is fine, but the problem is whenever the leaves get too big, they yellow and die...

PLEASE HELP!!!!!!!!

Those are too far gone imp.... id start from scratch.
If you really want to save them, run plain bottled water through them (twice as many gallons of water as the size of the pot, so a 2 gallon pot needs at least 4 gallons water). Then wait a few days and then start slowly reintroducing nutes, half strengths at first then up to full after a week and a half or so. But its probably too late...

I almost cried when I seen them...... May god have mercy on your soul

U SHOULD HAVE ASKED FOR HELP WEEKS AGO BY THE LOOKS OF THINGS....tHEY LOOK HEAT BURNT, NUTE BURNT, AND CAL/MAG DEF..SAY BYE AND START OVER..SORRY BEST OF LUCK NEXT TIME..

They need magnesium..........