Tips of fan leaves turning purple

[Safe Gardener]

Either or both, as it will reduce the light intensity.
Were the plants growing healthy after your final transplant, before you put them into flower? (or in early flower) ? if not then that may have compromised them a bit. as would being completely rootbound before you transplanted them.
VG

I’ll turn then down at lights on this evening. I’m going say a little from column A and a little from column B as far as plant/root health at transplant. It was root bound to some degree but grew really well for a few weeks before I put it in flower.

 

[Ca++]

Batteries replaced, I’ll have a high and low temp tomorrow. I run lights on 5PM -5AM, If I were to guess I’d say high temps with lights on is no more than 80F. Will update after a day with the thermometer/hydrometer in the tent. Air movement is less than I’ve provided in the past also. I’m only relying on air exchange from the 4” duct fan feeding my DIY 5 gallon carbon scrubber. Maybe add a fan in the tent?

Hard to comment on your extraction, but the temps will be useful.
It's not a cellar floor is it? That can chill the pots unexpectedly.

Lots of heavy dry-backs to wilting may be key here. Roots can only be dry for a while, and once into bloom, many plants won't grow more. P fixation in dry soils is a thing to, and I reckon that's what's niggling me. Heavy dry backs, cold floor, cold water, I think that is where I have seen this indoors. A cellar I left to a friend when I moved out. So I could never really say what the problem was, as he created a list of them.

 

[Safe Gardener]

It's not a cellar floor is it? That can chill the pots unexpectedly.

Lots of heavy dry-backs to wilting may be key here. Roots can only be dry for a while, and once into bloom, many plants won't grow more. P fixation in dry soils is a thing to, and I reckon that's what's niggling me. Heavy dry backs, cold floor, cold water, I think that is where I have seen this indoors. A cellar I left to a friend when I moved out. So I could never really say what the problem was, as he created a list of them.

You hit the nail on the head with the basement floor. I usually use a platform to keep them off the floor but wanted the extra space this summer for a seed run that I did. Didn’t even think about it for the fall. I’m about out of space but I’ll see if I can get a 1” of so off the floor.

 

[TanzanianMagic]

I’ll know daily high and low temps soon. Just replaced the batteries in the thermometer/hydrometer.

I’d have expected the soil mix to be a little heavy on the nitrogen but I can add some if they continue to yellow.

I don't know what nutrient solution you're using, however when they start to flower you should go from 5-5-5 in veg, to 10-5-5 in flower, and slowly increase the nutrient concentration until the nutrient deficiency goes away.

 

[PadawanWarrior]

I don't know what nutrient solution you're using, however when they start to flower you should go from 5-5-5 in veg, to 10-5-5 in flower, and slowly increase the nutrient concentration until the nutrient deficiency goes away.

I think you have that backwards. In flower you want less N.

You hit the nail on the head with the basement floor. I usually use a platform to keep them off the floor but wanted the extra space this summer for a seed run that I did. Didn’t even think about it for the fall. I’m about out of space but I’ll see if I can get a 1” of so off the floor.

I agree with @Ca++ . P deficiency. Maybe some molybdenum deficiency too, but mainly P.