Yes and no. You can look up a VPD chart, but insteaf of the inside temp of the air in the tent, use a no-touch thermometer to take the temp of the leaves and use that number instead of the temp.
I'd say probably should have already. What I think is you are hitting dew point when the lights go out and the temp drops. Many don't even realize this happening.
The biggest thing now is get a fan moving the air around the plants and buds to prevent condensation on the plants.
How much, how often, and what medium you growing in? A plant drink no more than a teaspoon a day, You could have nitrogen burn too, how often and how much are you feeding? Lastly are you using calmag?
My outdoors potted are drinking a gallon to run off everyday. I have a two liter jug I fill up and pour into the front (flood) and than do the same to the back. That liquid is sucked into the soil almost immediately. There is no hard and fast rule the only thing I would say is better to under water a bit than over water a bit. The bigger your plant gets the heavier your water requirement. The more intense the sun the heavier the water requirements. On a cloudy day I may only give them 2 liters.
My watering schedule is day 1 water, 2 and 3 wait, day 4 check and water if needed. Which they're pretty dry the 4 day. Since my last watering, on the 20th, I've noticed this discoloration. I watered with recharge and silica fertilizer. I haven't had this issue yet. Could it be the recharge/ silica combo? The pic of the leaves are what I pulled. Temp 84-88°. RH is 60-70% View attachment 1148707