Well high all ,1st im at day 35 of flower under 1200 w of hps,temps are 27c lights on and 50% rh,and lights off is 22c and 62% rh,on this grow i changed my nutes all my previous grows were with biobizz fishmix and bloom and some molasses and maxicrop seaweed,but this grow i changed that as i seen a grower on diff forum having great results with this granular feed called valagro made by maxicrop ,now ive given them a feed of this 6 weeks ago and just water since then ,on my previous grows i used feed with every watering in flower,with no yellowing like this grow,now theres some plants unaffected in the same grow now,heres pics i took today all plants are 5 weeks in flower,im using bio bizz allmix soil,i never ph or ec in compost,well my new set of seedlings and clones are getting my old way of growing and feeding there be no more yellowing with the new lot,but i still want to know whats up with these to learn more about this fantastic plant,,so all pics were taking today and pic with just the leafs are off 2 diff plants ,and some leafs came off very easy,any more experienced gardeners id appreciate some help or suggestions of what most likely it is and how to fix,as im still very much a learner after 5 years of growing, + Rep for any replys,cheers,,SOShiva