zinc or copper deficiency?

Hello guys

I am having issues with my plants, and it getting worse.

45 days into flowering, 3 galon pots, soil medium.

PH going in 6.4, run off PH 6.6

EC going in 1.2, run off 1.8

i started to see this yellowing of upper leaves some 2 weeks ago, at first i thougt it's an iron deficiency, but it doesn't look like iron now.
l can't see any reason for that, as it's not my first time in this set up, and never had such thing before.

i tried to add 1 ML per liter of canna trace mix, but it doesn't seem to help. so i shoot at zinc deficiency, went to a shop and grabbed half a kilo of zinc sulfate. added 3 gram of it to a 30 galon res of RO water, gave me 10 ppm, and watered. i hope that won't give me a zinc toxicity...

can someone help me identify the deficiency?
thanks in advence!

more pics -

Looks like magnesium to me. That intervienal chlorosis is very distinct.

What’s your soil nutrient values? Are you feeding? If so does it contain any Mg?

It is towards the top growth which is why I’m not 100% is Mg but your feeding habits should determine it.

This point in flower I noticed MJ likes additional Mg

Thanks for your answer nutty skunk!

i don't think it magnesium deficiency, as mag def atarts at the kower leaves, and my problem is in the upper leaves.
one more different from mag deficiency, is the shape of the yellowing straps bettwen the veins. in magnesium they are narrower, more at the tip and mergins of the leaves, and when it get worse, the leaves tips atart to burn and get crispy dry.

here it very diffferent, the yellowing straps are wider, and cover almost the all leaf before it burnt.

i am pretty sure it's some trace element deficiency. i eliminated iron deficiency, as my problem atart at the tips and mergins and not at the base of the leaf as it shuld be in case of iron def.

as for my feeding, i use mineral nuts, and supplement epsom salt regularly.

so my guess is zinc... could also be too much light.

Are the lower leaves affected at all?

The very top leaves show intervienal chlorosis with zinc.

In the first picture it’s your young/middle aged leaves that are most affected, not youngest leaves.

Zinc is needed in tiny quantities and if supplemented is often locked out by something else if problems don’t sort themselves out.

So what you’ve done regarding zinc is enough. If it progresses either something else or a lock out.

How much Epsom salts are you supplementing? Frequency too.

Below is a chart referencing how elements react with one another.

Zinc is attagonised by calcium, phosphorus and iron.

ifyou had a lock up and it affected the zinc up take, and then you added more zinc...you are still locked up.
I've never seen a flowering girl recover properly from this at that stage of flower. I hope yours recover for you.

Thanks guys!

the lower leaves are nor effected at all, there is some slight yellowing, but that's nothing.

the problem is mainly in the big fan leaves at the top. not the small leaves coming out of the buds.

my grow room is a sealed one with co2, so 80% of my water are recirculating from the AC and dehumidifire, and only 20% tap water.
i raise the ec to 0.3 before adding nutrients with botanicare cal mag. could the 0.1% iron in it is the thing that block zinc? it has never hapaned in many grows i had at this method.

i add epsom salt at about 30 ppm total (out of 600 ppm nutrient solution)

acording to those links, it's either zinc deficiency or light bleach

https://www.zambeza.com/blog-zinc-deficiency-a-nutrient-shortage-in-your-cannabis-plant-n154

http://www.growweedeasy.com/zinc-deficiency-cannabis

http://www.growweedeasy.com/cannabis-light-burn

I think you were right in there the first place and it is an iron deficiency. Zinc and manganese are related.

I would leach with some fresh water and add a moderate concentration of a balanced Grow ratio fertilizer to restore the nitrogen balance.

I stopped using bloom products a while ago and have not seen this kind of deficiency since unless I overfertilize.

This article supports what I am saying.

http://www.ilovegrowingmarijuana.com/iron-deficiency-plants/