What is wrong with my babies!?

I have a aeroponic type setup with 6 plants together very close together. In the past couple weeks I have noticed black specks on the bottom leaves. What could those be? But what is my main concern is I put them into flowering a couple days ago and now the biggest of them all has this gold discoloration to the top leaves. The only thing different that I added was I switched from a 600w MH bulb to a 600w HPS bulb and from 18/6 to 12/12. Also the nutes I use is Flora GH. I added 10 mL/gal of micro 7.5 mL/gal of grow and 7.5mL/gal of bloom. The bloom is the only new nute I added.
What do you think is wrong? I have spent alot of time and money into them and I dont want to see them die

is that one of the top or bottom leaves?

that is from the top of the plant
I dont have a picture of the bottom leaves, but they have little black dots everywhere on them

The discoloration effect you see in the picture literally came overnight and happened a day after I put them into flowering

Great color leaf...If u have your plants pic is more useful for make a true comment ....
Mg and cal or Fe can effect this figure leafs but your plants health is really important for cure ...
If u change your nut to your flower nut ...But by one day showed that ....!?

yo shit is FUCKED up