Bluewhidow into 5 weeks of flowering need help

i made a journal of my plant but something has happened big leafs are turning yellow and they are getting crunchie, im using dwc with ph of 5.5 and ppm of 1300 temps around 80 daytime 70 at nightime please help guys! if you need more info just ask

flush them quick..... salt build up on roots.....

for how long do i need to flush her?

I would say 5days to a week

damn is that good for her? i mean its in the middle of flowering phase....shes not gonna want nutes?