Leaves

the leaves on my buddah's sister recently started looking like the picture below.
Can anyone tell me right off wtf this is?
Thanks
I suppose I should have added some details, ppm of nutes and additives were like 600-700 in a DWC. I used the additives gravity and snow storm ultra and base AN connoissuer bloom.
Its been 8.5 weeks in flower and hasn't grown much (I think thats due to the fungaflor I mistakenly used)
Forgot to mention the leaves are drying out and if you fold one it just breaks.

It looks like maganese defeciency, did it start with younger leaves first, did they turn yellow first and then start to form these rust spots. What is your Ph is this soil or hydro? I would focus on adjusting your Ph thats what causes most everyone's problem.

hey thanks for the reply, it appears the younger leaves are nice and green. I've basically wrote this plant off because yield will be probably a zip if not less , which is about twice what the skunk #1 is gonna yield. Fungaflor really ruined this grow for me but the purple urkles and g99 aren't doing bad.oh I didn't answer your questions, sorry. its hydro , we keep the ph between 5.8 and let it drift up to about 6 or so then set it back down to 5.8.

Cool sounds good, could that plant just have been sensitive to the nutes, it might have been nutrient burn?

Dunno really, I thought I was having a rust fungus problem and used fungaflor ( my hydro shop told me to spray it directly on the plants, big mistake) but that was weeks ago and everything finally turned green and healthy again but now I'm seeing problems with the leaves on all the plants in there. although its late into flower and maybe what I'm seeing from the others aren't really the same thing but normal in this phase.I've got the other ones at a much higher nutrient level, just over 1000 ppm(this is a continous feed dwc type aerospring deal). You can see my stuff here.... https://www.rollitup.org/grow-journals/346967-my-first-grow.html
Thanks

Hey I like your buckets nice design.

thanks man, much thought went into them and I'm about to redesign a few things and possibly produce and sell a few, they really work sweet. The lid in the front although hard to get to when the plant gets bigger it still opens enough to get a meter in there or a water pump, thats currently how I drain them, gonna redesign that too so you just hook up a hose to the outside of the tote and just pump the water out with the internal plumbing/water pump. The filter is a little cramped too but removable enough for cleaning.
I really stand behind these totes, the design came out of necessity , the first design the plumbing didn't support the lid, the lid had a 6 inch net pot with a 5.5 foot pot plant in it with colas as big around as 2 liter bottles, the lid was a weakness and plants kinda toppled a little, thats when I came up with the idea of the plumbing supporting the lid( I just took a few mg of xans and had a few shots and I'm rambling but I like to be complete and finish wtf I'm saying).
My only problem with the totes is insulation, as long as room temp is kept at 70f the res temps don't go over 68f or so. I was thinking some kind of spray on insulation since I did paint the totes to make them opaque ,may as well save the money on the paint and have them sprayed by a professional with insulation, this should make them opaque also.