Reddish veins on 1 plant

I’ve got 5 plants, ILGM gorilla glue.
3wks in flower. This is the only plant with leaves in pic.
Using general hydroponics flora series feeding schedule
Soil, Ecoscraps.
Last run off ph5.92, watered today with 6.9 PhD water. Run off 6.05, ppm934
Any idea what these leaves are saying?

What is the temps in the grow tent?


77days, 72night

You would think phosphorus deficiency with it only being older leaves it’s on? Did you eat a bunch of Doritos before looking at your plants the other night? Lol gotta consider the soil ya started with too, and the temps is curious too?

@LoCoRock, what are you thinking about temps?