I too am an experienced troubleshooter, both for plants and for chem lab analytical equipment. I know, too, that it pays off to answer the stupid questions ... You have called tech support, so be prepared to answer the age old question:

Is the device plugged in? Har har har...

It matters what the NPK is. Trust me. If you are using a pre-fertilized soil, irregularities in your mixing may have left pockets of 'hot' soil and pockets of unferted soil, and plants need their soil to be consistent.
Females and males don't have different nutritional needs, and even plants of different strains entirely would be unlikely to show different symptoms at this stage based solely on how heavy that strain feeds- you'd see that more in late flower.
Spring water- this is an unknown as well. Is it packaged for drinking? Drinking water often contains minerals and metals, including sodium, that are too harsh for young plants, and not good in any life stage. It would be worthwhile to also check its ph - the liquid indicator drops are only $7 for the small bottle. Generally, tap water is the way to go with your houseplants.
15% humidity outdoors plus transpiring plants plus cups of water- your %RH is probably just about perfect. Your temps are not outrageous, but nearer the lights there are likely to be 'hot spots' and plant metabolism grinds abruptly to a halt at 96'F. Some strains are more tolerant of heat than others, and high Si levels can help, but 85 is as high as you want to go for any length of time.
Light- low leaves that receive no light will eventually yellow and drop. If your light pattern is irregular, you could gain by turning and rearranging the plants periodically.
Bleaching- This does happen in high temps and is commonly seen on leaves that are quite close to a light- too close. But pictures are important to determine the cause, since different patterns mean different things.
Finally, the feeding of 20-20-20- hm, let's see... you actually gave them 5-5-5 and if they had at least 5 sets of adult leaves at the time, that was not an inappropriate dose unless the soil already came fertilized. It isn't ideally balanced for pot though, and you would do yourself a favor to hunt around for a fert with a higher first number for vegging. Do not use azalea or orchid food though, because the pH is buffered in the 5.5-6.5 range for acid loving plants.

As soon as you can post up a pic...