Plant seems healthy but strange leaf spots?

[davecw]

Anybody know what's causing these leaf spots?? Other than that the plant seems healthy...

DWC:
1. Are you growing from seed or clones? Seed
2. How old are your plants? 7 weeks
3. How tall are your plants? 12"
4. What type of hydro system are you using? DWC
5. What brand/type of nutrients are you using? GH Flora Trio
6. What is the Ph of your nutrient solution? 5.8
7. What is the PPM/EC of your tap water? R/O water 0 ppm
8. What is the PPM/EC of your nutrient solution? 760
9. What is the temperature of your nutrient solution? 66 F
10. Does your PPM/EC show a rise or fall when you do your daily PPM check? Fall
11. Does your pH show a rise or fall when you do your daily check? No change
12. Do you foliar feed or spray your plants with anything? no
13. What kind of lights do you use and how many watts combined? (HPS, MH, fluorescent, halogen, incandescent "plant lights") LED
14. How close are your lights to the plants? 24"
15. What size is your grow space in square feet? 40
16. What is the temperature and humidity in your grow space? 78 F 58% RH
17. Have you noticed any insect activity in your grow space? No
18. How much experience do you have growing? First time

 

[GrowHobo]

Cal or mag? I’m not sure. New growth looks fine though. Realize the damaged leaves won’t get better look to the new growth for plant health. Whatever caused that started more than a week ago imo. Good luck.