Plants getting ill whats up

hi everyone new to growing need little help pls. i have got 4 barneys pineapple expess autos at day 31. im growin in a 110cm x 65cm x 160cm tent 400w hps with fan and filter temps are 27 - 29 im growig in soil ,im watering when pots get light with 3ml litre canna flores every other watering humidity bout 48%. The problem is last two days the leaves have gone light green / yellow with dark veins i know somethings up but not sure what. im heading towards thinking maybe magnesium def thats where i need your help ne greatly appreciated thanks. last pic shows clearly what i mean.

Hi - did you measure the ph-value of run-off water? - those defficiencies often occur when ph-value is slightly off. Not a pro here, but that's where i would start looking for the problem.

Hi brimi thanks for quick response. No never mesured the runoff only whats going in which is 6.2 - 6.5 ill give that a try and see what it comes out as could be interesting see if it goes up or down might be the issue. how do i give u rep bud

it looks to be the beginning of a mag-def. but you have to make sure your giving yr plant what it needs. not familliar with canna flores but u want to make sure somwhere in your nute regimen there is magnesium. if there is then you have another prob causing the lockout. ph is the perfect place to start. not just a good ph but constant as well fluctuating ph can cause def's and lockouts.

Hi Hoenheim thanks for reply. canna flores has 0.5% mg is that enough if not will epsom salts correct the issue ph is pretty constant thanks again. plus rep now i know how

i wouldnt try epsom salt yet. as i understand it doesnt take a huge amount of mag to complete a grow. if there was none in your nutes. a few foiler feeding PER GROW would be enough. if it is indeed what the problem is than it is caused by lockout and adding more would add insult to injury. sorry i cant help you more on the prognosis but i can advise you not to add anything as its harder to fix an abundance than a deficiency. goodluck bro

Hi - i'm not really sure but some soils change the ph quite a lot. If it's because of an off ph you definitely don't want to give your plants anything else but ph-adjustment. But since your ingoing water is adjusted i would have thought it would be good unless you use some soil with a different ph. But plant got this big in it, so not really sure. Maybe somebody has a better idea of what could be wrong.