Dead leaves 4-5th week of flowering

Ok, so 2 NL plants in a 5 gal DWC bucket

GH 3 part nutes, latewood's recipe, now in the 4th/5th week 0-1-2 ratio. PPM's have been around 1200-1300 the last few weeks, PH has been checked almost every day, using tap water with a base PPM of 175-200. So i understand when plants leaves die off late in flowering, but this early and in this quantity? all of my leaves are dying and falling off..buds seem to still be forming fine, but wtf? root rot, nutrient lockout, nitrogen def? this is only my 3rd grow, and my first grow actually having females and flowering them so im not sure...they were doing damn fine during veg and first 3 weeks of flowering but now the leaves are all dying and stuff...whats up? any clues?

Forgot some other details

Northern lights
5 gal DWC
GH 3 part nutes with Fulvic acid, Floralicious plus, and superthrive
2 6" air stones
400W HPS
temps day-80-83 but with good constant airflow, so actual temp around plant might be high 70's

pretty sure no light leaks, havent seen any male flowers at all for hermies...whyyy are my leaves dying?!? i added a bit extra Grow from teh 3 parts to have some more nitrogen etc available to help stop this death, but i dunno...think my yield will suffer from this or is my plant just doing its own thing and doing fine?? also, what weeks do people usually pull NL? end of 8, or wait till 9 or what? Nirvana seeds(where i ordered), says 7-9 weeks, so no clue which means i need to get a 30x lense or something.

I've done his NL and it was 8 weeks for me. I'd like to know what your runoff PH is. Looks like a possible lockout (Mag.?) to me.

i dont have runoff, its a DWC hydro system..the roots sit in an aerated nutrient solution..should i flush with PHed water for a few days?

Whoops, I missed DWC. Yes I would flush though with correct PH water. I hope this works for you.

this is what hte leaves start to look like before dying...according to george cervantes books, this looks like nitrogen/magnesium deficiency..i added some epsom salt to my nutrient solution and PHed it and gonna see what happens.

Looks like N def. to me. At weeks 5 or 6 weeks it would be OK but if it's starting in the 4th week you probably have a little lockout taking place. Might be a good time for a flush and then 1/4 strength nutes. It doesn't look so bad that it will significantly reduce yield.

Quote:

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Originally Posted by PdoubleOTY

.i added some epsom salt to my nutrient solution and PHed it and gonna see what happens.

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That's going to make it worse. Pale stripes combined with burnt tips = lockout/overfert.
Proper fix is a res change to correct pH, then go to a slightly lower dose of your base and micro than what you had been using, and work back up to the desired strength, stopping if you see tipburn. You can also do a light foliar mist with your micro fert mixed WEAK!!! Don't get it on the buds if you've already got them.
No superthrive in flower, ever. It's way too much N for a flowering plant and can contribute to that sort of problem.

ah thanks for the help guys. ill be sure to do a res change and what not right after im done posting!