problem plants with intervienal yellowing

[.co.uk]

Hi, I`m growing the cheese strain and having some problems I cant seem to get on top of. My last grow was down 2/3rds in yield and it looks like the same problem is occuring again.

I`ll add a couple of pictures to see if anyone here can see where I`m going wrong.

I`ve treated with epsom salts at 2 teaspoons per gallon thinking its a magnesium deficiency but it doesn`t seem to be helping here. Having said that I took a couple of cuttings from the same plants for a friend and they had the same problem, but epsom salts and strict control of ph (it goes up constantly and needs a lot of adjusting to keep down) seems to have gotten rid of the problem and they are looking very well now, being grown in the screen of green method. They`ve filled the net up and now budding like crazy.

They`re a few weeks ahead of mine and I want to try and get mine back on track.

I`m having the same problem with fast rising ph values, but keeping on top of that. The same nutrients (Cana Coco) and medium (Cana Coco mixed with 30%clay pebbles) are being used in both grows, I just cant figure it out.

My grow before last came in a little low without really doing anything about the yellow intervienal discolouring, and then my last grow was lousey and as stated above was a good 2/3rds down on normal, they just never filled out. I did get a bit sloppy during that grow and the cf and ph readings got out of hand for a while, stupidly I let myself get distarcted. I know of other growers growing from the same stock that have had bumper grows, so what the hell am I doing wrong. I`ve come across a lot of different problems in the past but never this one.

Please help if you can, thanks guys

[.co.uk]

Bump. Any one any ideas please?