Hydro plant dying. Please help

Was looking fine until 3 days ago. Then leaves started to curl under and now look like the picture. PH has been checked and some neutrients added and new air stone and pump. Some leaves are still green with a smell to it. Can anyone please save us

more info and pics would be awesome.

you didnt post a picture, re-calibrate your ph meter just to be sure

got screwed one time my ph was at 4.3 when I thought it was at 6 for two weeks

how do your roots look? I had a dwc and the air pump broke, the roots started to die but after getting another air pump the plant survived and produced some dense tasty buds.

Reduce Feed Strength , from the symptoms you told us it could just be overfeeding , leaves will turn from shiny green to dull dark green with possible leaf tip burn, but photos would be great to allocate the problem