Help a Sister out! Plants leaves dying!

hey guys! Im in week 5 of 12/12 and my upper fan leafs are turning yellow and some are shriviling up and dying! check out these pics! i just need to know if this is normal! las week i had air conditioner issues and the plants got hit with some 90 degree weather! i hit them with a little extra co2 when the temp was up, maybe the heat killed them?? the temp has been steady for almost a week now, tell me what you think !! love ya!!!! Lace

I would almost bet it was the heat, Stressed them out a little bit, Other than that the plants still look Decent. Regulate the air flow and heat and they should be alright, No life threatning problem here I dont beleive

yeah maybe move the lights up ... that happened to me too

I see some shrivelling, but all in all looks good

Heat burn will make the leaves crispy and flake off. Thats a nute issue, you are losing calcium among other things while your plants are trying to produce flowers. Try some calmag and something with a NPK of 5-10-5 while flowering.

i used cal mag in my last nute change 4 days ago! should i add more? my ppms are about 1600 right now, temp is about 81 up top and 79 in the bottom. i just added another 100ml of cal mag to my 10 gal res! lets see!

Oh, do you think i should pull any of these? i tried one, it didnt wanna come off so i left it!!

nope let them fall off naturally...the leaves can still synthesize