wordd! its fox farm so i didn't htink it wud be that bad but right now i'm not giviin them any more nutes so i guess its hud be aight - anyways they only gotta survive another week or two
It doesn't really matter who makes the nutrients, if you give the plant too much - it'll burn.
What happens is this -
Roots use osmosis to draw in the nutrient solutions. Osmosis is the process by which fluids pass through a semi-permeable membrane (in this example the root membrane) and mix with each other until the concentrations are the same both inside and outside of the root membrane. Sugars and salts are concentrated in the roots, so the EC inside the root membrane will nearly always be higher than the EC outside the root membrane.
What happens when the salts build up to toxic levels in the soil medium is that the process of osmosis continues, but it reverses. Instead of the plant drawing salts and ions into the semi permeable root membrane, it actually sucks them out instead due to the EC levels inside and outside the root membrane now being reversed. This is exactly why you need to be careful of what EC levels you feed at.
So because moisture and nutrients are now being sucked out of the plant, instead of in, the plant starts to show what we describe as 'burn' symptoms which are really deficiencies. That's why it's not always easy to tell the difference between a plant leaf that's burn' and one that's nutrient deficient.
What usually happens, is that the grower doesn't realise what's going on and 'assumes' the plant is deficient and simply gives it either the same dose of nutrients or increases it - making the situation even worse.
The only solution for a badly over-fertilised plant and pretty much the only time I'd recommend it - is to flush with plenty of plain water to remove all those excess salts and start again with a fresh slate. Even then in my opinion the better option is to simply flush once and then repot.