Plants Sick plz help cant figure it out

Hi this is my first time posting on these forums and id like to say ive found alot of info here, but i cannot figure out what is wrong with my plants and im worried about thier health cause due to recent problems ill need to continue cloneing this mother to continue my genitics or lose them and i wont be able to get them again.


recently ive noticed the tips of new growth having intervienal yellowing, while on other parts of my plants im seeing yellowing viens and bad necrosis twords the bottem, and ive noticed, tho u cant tell as well from these pics, the yellowing tips are combined with very smalll brown spots and im worried because ive looked everything up i can find and i cant diagnose my problem,

i was leaning twords Mag def but i dont see how it could be on every plant at the same exact time, infact i dont think its possible, i dont give nutes to the smaller plants yet and my big one ive been giving 1 and 1/2 tsp fox farm grow big, along with suger daddy additive witch is sulpher and mag, these pics ive included are of 3 differnt plants

this all appeared at the same time on my plants while all were on differnt watering scheduals and nutes, my area i grow in is a inclosed box i made myself 2.5w x 4L x 5.5h, inside the box i had 2 fans blowing on the plants and i used Yeast DiY Co2 Genorators, 20oz bottles, had 2 of em in, i left my intake and exhaust fans off but open to allow old air to leave,

i use a 400watt hps is lil over 1 and 1/2 ft from tallest plant 3-4ft away from lower ones, my temp was avg of about 72-75 now that ive taken the steps i have its a little lower, humid is typically about 40-50 more twords 40 then not, my soil is out of the bag Promix BX, and ive not been able to check my PH due to having bought a bad meter that dosnt work and needing to buy a new one

from what i can see i would think this is a problem that all of them are sharing but i cant figure out where its from

Yesterday i turned my fans off inside took out my co2 and turned on my intake/exhaust too see if its something envirormental, ive also started foliar feeding my big one with 1/4 tsp FF and lil tad extra sugar daddy for the extra mag to try and correct what i thought the def was, i give an extreamly small dose to the smaller ones of foliar spray, all and all i cant figure it out and i need some help if someone can, i want to correct this problem befor it becomes a major issue, as it stands i need to be cutting clones immediently, the plants getting too big and i need to be able to trim it and make healthy clones asap

Please if experianced growers have any ideas, help me out plz

More Pics here

also i should add that these are in veg, and on a 24/hr light cycle

plz if anyone could help id appreciate it

ty for reply and welcoming me , yes i have read everything i can find this is why i came here, is it possible that this is a Def when all plants show the defects at same time? the younger ones dont get nutes yet, i was thinking it was more of a global evo problem, like maybe my ph? tho still i dont know how it could be this when the ph lvls are more then likely differnt per plant due to one getting nutes and the others not, could chorine in my water do this, or maybe too much Co2? i plan on getting something to test my PH asap but i was leaning away from it being this due to all the plants showing it at same exact time, also the necrosis and yellowing viens confuses me, maybe its a lock out or somthing?

This was my 1st thought.....

Nitrogen Deficiencies:
Plants will exhibit lack of vigor, slow growth and will be weak and stunted. Quality and yield will be significantly reduced. Older leaves become yellow (chlorotic) from lack of chlorophyll. Deficient plants will exhibit uniform light green to yellow on older leaves, these leaves may die and drop. Leaf margins will not curled up noticeably. Chlorosis will eventually spread throughout the plant. Stems, petioles and lower leaf surfaces may turn purple.


Figure 9

this is why im confused my growing dosnt seem to be slowed too much and they are not droopy, only the bottem of the plants, specificly a couple fan leaves are yellowing uniformly and have necrosis( i think this is due to a spider mite problem i got rid of 2 weeks ago), the top most of the plants are having intervienal yellowing and spiratic leaves have yellowing viens, some leaf margins are curling up and some leaves are becomeing V shaped, also this all happened at same time with my smaller ones, i mean i could understand if they were all same size getting same nutes but its 100% differnt watering/nute schedual, on the babys the intervienal yellowing is on only the newest growth and no where else, all other leaves remain very green, is there something that can do this other then def? like co2 toxicity or not enough oxygen? even a ph lock out sounds inprobable to me due to it happening to all plants at once

bizzzzzump

i think it is high ph and it is causing lock out. i would check that first.