Only pertains to flowering plants. The issue shows up at 6 weeks.

What is your experience level? (first timer, novice, experienced...)experinced

Your Equipment:
.1) Type and wattage of lights. (MH, HPS, CFL's, tube fluorescents, LED's) HPS 1000 and MH 400 for last 2 weeks
.2) Distance from tops? 12-16"
.3) Reflector type? (cool tube set-up, bat wing, enclosed reflector, bare bulb...)Vertizontal (1000) and Sunsystems for the 400
.4) Is there a consistent fresh air supply? 750 cfm
.5) Do you have an exhaust fan and a circulation fan?Yes
.6) What are the bulb wattages, kelvin ratings, and schedule? 1000-6500K, 400-2700K

Your medium:
.7) Specific brand and type of soil, (coco, peat based soilless...) and anything you've added to it. (vermiculite, perlite, worm castings...)FF Ocean Forest
.8) Size of container.3 gallon
.9) Did you use peat pucks (or similar) to root clones or germinate seedlings? no rockwool cubes

Your nutrients and water:
10) Source of water? (tap, bottled or filtered) What's it's ph before adjusting?RO-6.0
11) Method of checking water ph. (ph pen, test strips, aquarium test kit...) drops into water and color match
12) Method of adjusting water ph. (phosphoric acid, white vinegar, hydrated lime, PH Up...) Dolomite if below 6
13) Specific brand and N-P-K ratio for each bottle. List dosages (quantity per gallon) and current feeding schedule. One feeding in flower cycle, Floral Nectar 5 drops in a quart and Ultra Snowstorm 5 drops in a quart...it does without these nutes also
14) How often are you watering between feedings, and how much per watering?I water about every other day 2 cups or so, only when plants need it
15) Any additives or tea's? (Superthrive, CalMag, molasses, Mother's Earth...)No
16) Are your ph levels stable, or do they fluctuate?Stable
17) What is your ingoing water's ph? ...your runoff ph? Have not checked runoff. 6.0 incoming
18) Do you foliar feed? If so, with what, how often, and at what time do you spray? No

Your growroom:
19) Indoors or outdoors?In
20) What size of closet, room or hut?5x10x8
21) What are the temps and humidity levels while lights are on? ...With lights off?Not measured, but currently 75-80, unk humidity, lights off 60ish
22) Have you seen signs of insects in the growroom?No

Your strain:
23) What strain are you growing? (Indica dominate or Sativa dom?)White Widow, Strawberry Cough, Haze, RMT, plus indica and sativa dominates, 8 different species
24) From seeds or clones?Well they all started from seeds, but live as clones
25) Is this an autoflower strain? Nope

Ok that is about the best I can do. I don't have runoff, so no idea what the pH would be. This happens to every one of my strains at about 5-6 weeks into flower. It happens if I give the flower nutes or not.

Where do you get straight molasses and how much in a gallon and how ofter Rusty?