help yellow brown

First post here so I hope its where it needs to be. I have a lot of growing under my belt and can usually figure problems out on my own but this has me stumped. All of my plants have turned yellow with red stems and brown patches on leaves. I have never had this problem before and could use some...

Hi there woke today to find my ladies struggling I checked the forums n threads but can't work out what's wrong any advice would be appreciated she's in coco on 12/12 ph'd water to 5.6 on the routine of feed feed flush I have posted a few PUC have a look and let me know that yous think