please send a pic without the lights on. When you have Sodium or Halogen lights on, the yellowing makes it very difficult to diagnose
It appears to be a mold or bacteria but we need more information to make a good diagnosis
so, new pic…1 close, 1 showing more of the plant
environment - type of light/s, how close to plant, type of plant/s, Rh, Temps, Substrate (soil / hydro / organic)
Fox farm happy frog soil using fox farm nutes my room temp it 80 and humidity at 38
I’ve had something that looked just like that a while back and it ended up being nitrogen was to high for the stage of flowering it was in causing the micronutrients and potash to be getting locked out. I was also using foxfarm nutrients at the time. They are pretty strong, so once I was able to get that lowered and adjusted it was back on track. Not all of the leafs will return to normal some of them not at all.the best part is that it still turned out great. Hopefully the same will happen for you… Good luck and nice grow. 
Thanks hopefully looks pretty bad I’m in the 7th week of flower
Are you misting the plants with anything? A humidifier? Did it start at the bottom and work its way up? How long has it been going on and is it on more than 1 plant?
It does look like yellow leaf spot (as Adam coined) but when I have seen it, it is usually more circular spots, begins at the bottom of plants and EVENTUALLY reaches the tops.
Ask @MDBuds about a Copper solution for treating it…especially if it is fungi. It usually begins looking like “pimples” on the leaves
@Junnie360 I’m with @Athan1982. It looks like you have micros locked out from excessive nitrogen in flower. Fox Farm nutes are great but I would only use them at about 1/2 the recommended strength in their soils because I’ve seen this lock out happen a lot in flower with people using Fox Farm nutes at full strength.
@Mrb53004 @CkNugz leaf septoria is a possibility too but I don’t see any of the necrosis that would come with an infection this bad so it’s likely just nutrient burn and lockout from dosing too high with the Fox Farm nutrients. Leaves are dark green, burned at the tips, and spotting from calmag and potassium lockout. It’s also why his buds aren’t very big for 7 weeks. Need that potassium and phosphorus for big chunky buds.
One way to know for certain as leaf septoria is a bacterial infection is to choose a leaf and put some milk on it once a day. If it keeps progressing it isn’t leaf septoria and it’s nute lock out.
@Mrb53004 I do know how to make an ionic copper solution as well that is great for killing fungus and algae but it can easily cause copper toxicity if applied incorrectly.
Same as making CS but you use copper instead and when you add the L-ascorbic acid to reduce and stabilize you boil it down to concentrate it. You end up with an almost greenish blue solution that you then mix with distilled water to 20 ppm and mist leaves.
Perk is it also increases photosynthesis by increasing plastocyanin production.
Con if used improperly can cause copper toxicity. Stunted roots, stunted growth, burned leaf tips, and possibly plant death.
Thanks I was thinking that to imma flush them real good and try half strength. I have 7 plants and only 3 of them look like this.
@Junnie360 are all of them the same cultivar? Some strains are nute sensitive too so if the 3 are the same and the other 4 are different strains it would make sense if you’re giving them all the same nutes.
The 3 that have it is the cheese. And the other ones are g13 I do give them all the same nutez. How do I fix im on week 7 and the cheese is 8 to 10 weeks to finish should I just give her water
@Junnie360 yeah just flush and give one final feeding 1/4 strength then just water last few weeks.
Thanks for all the help .I needed it .