plant deficiency

[Lyle]

I am getting gray spots on many of my plants,  I think it is an iron deficiency however it does not look much like the pictures i have seen of iron deficiency.  any thoughts would be helpful.

PH 7.4

Ammonia 0

Nitrites 0

Nitrates 160

cucumbers:

Broccoli is not as bad but starting to show up as well

[Margaret Corbett]

Do you get any dew or moisture on your leaves?

It looks a little bit like the sunburn I've had from getting water on my outdoor

vegetables on a sunny day.

I don't know, of course, but?

[Lyle]

should have also added that it is an indoor system, 100% artificial light.  currently have a MH bulb on them.   

[Keith Rowan]

might not be enough light...