HELP- Having a problem at end of veg!

Can anyone out there tell me what is happening to lower and top leaves?
These are 4.5 weeks old and just moved to flower. the upper and lower older leaves are showing yellow spotting between viens, but look like it is starting at the vien and progressing.
Ive checked out the problems forum, but nothing there looks exactly like my problem.
I used MG potting soil, and MG nutes only twice during veg.
I dont know what is going on, as I am a fairly new farmer.
Is this trace element lock up?
PLEASE HELP, I have Medical cond. that require A daily toke or two, that I cant pay for, so Im trying this again after one failed attempt.

doesnt look like theres too much to worry bout dude - just let them do there thing

if the prob persists make sure you give them a nice flush - 3 x the container size! whats the PH of your soil and water ur giving them?

if anything i would maybe say its something to do with ph - give them another week and if the prob is still there or getting worse - give me a shout and ill try help you as much as i can

Thanks england for the reply, I think Ill give them another week and if they dont look any better ill flush um good!
The ph should be fine as i am using zeph hills spring water, not sure about the soil, I figure that out of the bag MG should have the proper ph.
Ive looked around a little more since posting this , and I think it might be a zinc or iron def.
I dont have a ph meter yet, cuz Im broke, I know that I need to get one for sure! Thanks again dude

Looks like first signs of a Mg def.