In 2 1/2 gallons of water.
Add 15cc peroxide
Add 2 cc SuperThrive
Add 25cc Viatimin B1
Add 3 cc ProTekt
Add 30-10-10 fertilizer
Add 5-50-17 fertilizer
i did some digging....
that is what is killing your plants, in combination with the high heat.
cannabis can withstand high temps with ease if it has the right moisture levels
and fert levels.
your over feeding, bigtime, for soil.... the high fert levels are wicking moisture right out of the plant (ie burning) you need to get those salts out of the soil!
flush the plants, use 3 times the amount of water that the container the plant is in, if your using a 1 gallon pot per plant, than each plant will need 3 gal of water to be flushed.
i know its a pain in the ass.... but you dont have many options left.
let them dry out for a few days and see if you have any green growth returning....
imho, i would also get rid of the vit b... no telling what that is doing to your soil's ph levels as well.
i think your getting too complicated with the ferts, honestly. its a very easy mistake for a novice grower to make (ive done it myself, more than once, lol)
you have to treat ferts like its herion for your plants. too much will kill them with a quickness, to little will have no effect, and cutting them off all of a sudden will make your plants go into withdrawel, so to speak, lol... not really withdrawel but the sudden lack of nutes in the medium makes em start consuming there fan leaves, similar to the way a mammal will burn fat when it cant eat.
ps- the NPK levels of the nutes your using are off the chart for N and P.... hint hint... too much. cut down the concentration when you start feeding again, like 1/2 strength. i would say 1/4 but your already flowering, the ladies need all the food they can get, but like i said, its easier to overfeed them and kill them than it is too feed them just right.
and never feed a plant in soil everytime you water.... feed them 1 out of 3 times for starters, even 1 out of 4