Need Some Help Here With My Indoor Grow ASAP

Hey All, 
 
Thank you for by CouponDropDown">checking out my post.  I will try to be as descriptive as possible here about the issues I'm having with my second grow.  If I don't include some important detail, please let me know and I will provide it.  
 
As stated earlier, this is my second grow.  Everything started to go a little wrong about 3 weeks ago or about a month into flowering my babies.  During the vegging cycle I had 6 plants planted in anywhere from 3 gallon pots to 10 gallon pots.  The strains were 1 White Widow, 1 Agent Orange, 1 Tang, and 3 Blue Widows.  I used Happy Frog Soil and 1 1000W HPS light.  During the vegging cycle, I never dosed with any kind of nutrients.  It just seemed like they didn't need it and I didn't dose during vegging of my first crop so I figured I would keep things the same.  I did some LST on the 6 plants so that's why they look bent over in the pics.  I have and continue to use tap water as there is no money in the budget for an RO/DI unit.  The plants that I'm having trouble with are of the Blue WIdow strain mainly.    
 
Okay, so that's the veg cycle.  Once I started to flower them, I noticed that the bud sites were turning pale green.  I figured this was because the plant was pulling all the nutrients from the leaves and putting it into the bud so I decided to start using Fox Farm Big Bloom nutrients.  I only used about a third of the recommended normal dose and did this just about every watering for about 2 weeks.  At this point, my plant had turned very dark green and I was just starting to notice light burn marks on a few of the fan leaves.  So I stopped using the nutrients.  It was also about this time that I noticed that the plants weren't growing as robustly as before.  It was as if they were stunted.  The buds keep getting bigger but the plant as a whole isn't by CouponDropDown">continuing to grow.  I realized this when I put smaller plants into the flowering room and as of today, the new plants are roughly double the size of the plants that had been flowering for a month already.  I figured this problem would go away if I stopped using the nutrients cause I thought it was nutrient burn but the problem has escalated and today I figured I would do something about it.  As of today, the majority of the leaves show some sign of distress.  Crumbly edges, very dark green color, and some of the leaves are falling off and dying.  
 
 
Also....I have been noticing a few gnats flying around.  I'm talking about seeing 1 or 2 a week so I didn't think it was that big of a deal until I moved one of the affected plants today and looked closely at the water run off in the tray below my pot.  I saw about 5-7 gnats stuck in the water and a few worm like creatures in the water.  They were white and looked like worms opposed to the caterpillar like larvae that I have seen from fungus gnats online.  I also checked the first two inches of dirt and couldn't see any sign of larvae, even with a loop and a magnifying glass.  
 
This problem is mainly affecting the blue widow strains but I can see it progressing into the other 3 strains.  Another of my plants, a Juicy Fruit teen, is also showing signs of distress and I have put pictures of what it looks like in the photo section.  I really would love some advice here.  It's kind of an embarrassing issue as this didn't happen during the first grow. My water run off PH test today was about 6.5 or 7, not too far off and the temperature in the flowering room is about 75-80 during the day and 65-70 at night.  I thought that maybe I had spilled nutrients on the fan leaves and this burned them but that doesn't explain the stunted growth and very dark green leaves.  
 
Thanks for any responses!