tan leaves, need your advice

hello all,
i kindly need your experts advice.
i have one girl, now at the beginnign of her 4th week of flowering.
she had a rough life, overcame severe problems twice (necrosis spots at week 2 of veg and all around pale color at week 4), and now she's having another issue.
leaves all around the plant are getting this brown-purple tan, at the moments this is only seen on the top side of the leaf.
it seems that the pistils are also getting colored and im afraid this is not phenotype.
this problem is spreading fast and im afraid it will have severe consequences that won't allow her to finish properly.
as i mentioned, this is the only female i have so i must not screw this up.
i also have a male which i kept for pollination (outside the grew room) and he doesnt show any of the signs the girl is showing.
i did a mistake using a pre-fertilized soil of unkown origin and im afraid this might be the cause of all the problems. but now it's too late to change that so im trying to adjust and so i feed her little dosages of ferts with little amount of mollasses and only feed her once a week. i was under the impression that the soil is heavily fertilized so hence my feeding schedule, but i might be wrong and maybe the problems are due to lack of ferts? idk...

please view the pics and the info below and advice

thanks!

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What is your experience level? novice

Your Equipment:
.1) Type and wattage of lights. HPS 400W
.2) Distance from tops? 9 inches
.3) Reflector type? cool tube set-up
.4) Is there a consistent fresh air supply? yes
.5) Do you have an exhaust fan and a circulation fan? yes

Your medium:
.7) Specific brand and type of soil no brand. fertilized coco mix
.8) Size of container. 3 gal
.9) Did you use peat pucks (or similar) to root clones or germinate seedlings? no

Your nutrients and water:
10) Source of water? tap What's it's ph before adjusting? 7
11) Method of checking water ph. test strips
12) Method of adjusting water ph. phosphoric acid
13) Specific brand and N-P-K ratio for each bottle. List dosages (quantity per gallon) and current feeding schedule. biobizz ferts, little amounts according to the all-mix charts ones every 3 or 4 waterings
14) How often are you watering between feedings, and how much per watering? 2-3 times between feeding, 1.2-1.5 liters wach time
15) Any additives or tea's? molasses
16) Are your ph levels stable, or do they fluctuate? stable
17) What is your ingoing water's ph? ...your runoff ph? ingoing 6.5 runoff 6
18) Do you foliar feed? no

Your growroom:
19) Indoors
20) What size of closet, room or hut? 2 x 3 x7
21) What are the temps and humidity levels while lights are on? on: 28-30 c off: 18-20 c
22) Have you seen signs of insects in the growroom? no

Your strain:
23) What strain are you growing? Indica dominate
24) From seeds or clones? seeds
25) Is this an autoflower strain? no

Looks pretty normal during flower.. My bet is this one turns a little purple on the fan leaves. At this point (4+ weeks), you should give it a good flush with water pH adjusted for coco.. Assume around 6.0 give or take. If you don't measure pH, just use water. Discard the drainage.. After it dries out a bit resume your feed/water schedule. Be patient and see how it's looking in 7-10 days. Keep in mind, in late flower some of the larger fan leaves will yellow (or similar) and drop off.. All normal.

Good luck!

Farmer Rich

thanks for the reply, Rich.

i really really wish that you are right and that this is just the phenotype, but meanwhile is has spread further and many leaves developed dark strips.
the pistils are becoming pink. some parts of the leaves that are not dark are loosing their green. this all thing is movingd down from the more mature buds to the lower ones.
small leaves within the buds has also started to gain dark strips. only thing that is good for now is that all these leaves are still stand normal and not curl down to die. i'll be smarter in a day or two...
anyway, i gave it a good 30 liter flush with adjusted water and finished with a full amount of food according to the scheduale. im thinking there is an option that some of the additivies are bad or react badley with the fertilized soil, so if this will keep worsten up i'll give it another flush whithin 3-4 days and this time hold the food.

wish me luck!

Farmer Rich, im glad to say that you were completely right! nothing but phenotype...

Attachment 288138

Sweet!! Thanks for letting me know.

Yeah dude. Those ladies look absolutely beautiful. phenotype or not, the purple color you see is not a bad thing. some strains naturally have it, but every strain can turn purple by decreasing temperature. purple absorbs more heat than green so plants that get cold can turn purple as a natural defense. it can stunt growth a bit, but wont harm your plants unless the cold gets serious.

and seriously, they look great. can't wait for my babies in week 2 of flower to look like that :jointsmile: