That looks like calcium and magnesium def and a nitrogen def.
Have you fed the plants yet? what and how much? Whats your ph of your water?
Your plants look plenty old enough to feed a well balanced 1/4 strength nutes.
this last post sounds about right, looks like that tip burn came in first, followed by the spots which would indicate ph being out of wack. when ph is wrong it will cause a nutrient lock out and thats why that spotting occurred. you should get a ph meter for soil and check ph of your soil. then you add appropriate ph water to pot so that ph in soil ends up settling around 6.5-6.8 this is the happy stage for soil.