Help please yellowing and browning

all my plants where very yellow the other day i got advice from someone on hear to feed them as they looked like they had a defficiency i have 9 plants but 3-4 dont look like they are recovering i have givern 1 of them a flush and now the ph off the run off is 5.8 and the ec is 0.8 i ran about 3 litres of phed water thru 1x6.5l thanks for the help also some have some brown spots apearing and im growing in coco under a 400w mh air cooled temp is 23

dont worry about picture 4 thats was when they where younger

more pics of them

ive seen a lot of problems like this, the cause can be one of several; lights to close to the canopy, overfeed, underfeed, etc. I got tired of dealing with all of these problems so i found a soil that grew my plants for me.. Next time you transplant use FOx farm Ocean Forest.. Just feed them ph corrected water and they will do great. all you need to do is supplement nutrients for flowering, No more veg nutes or worry about over/ underfeeding!!! Good luck

anyone else ??