Unless you raised the light for the photo, it should be much closer to the plants. The medium looks too wet, and bottom heat should be removed as soon as the seeds germinate. Fertilizing is not recommended until seedlings have their first set of true leaves.
Separate the seedlings into their own containers, plant the leggy ones as deep as you can, go easy on the watering and get that light right down on top of them.
My own experience with the phosphorus issue is that it has been transient and has corrected itself as the plants mature, unless the temps are quite cold for a long spell. I'm usually not concerned about it with seedlings. JMO

Yes that is the issue and yes it will go away all on its own as the plant matures. I agree with noinwi - cut the watering, lower the light - they are leggy already - and don't worry about the purple coloring.

Dave

I've also been experiencing this problem with both my tomato and pepper seedlings. My room temp is approx 75/76F but my soil temps are much lower in the mid 60's most likely due to the fact that evaporation cools the soil. As much as I would like to leave it be, I feel as though I should be doing something about it. I've read that warmer soil temps would rectify the problem and allow for more P absorption. My bhut jolokia plant is about 1.5 months old and although it's starting on it it's 3rd set of true leaves it's only 1.5inches high. The stem is deep purple and the older leaves are a bit purple with the new ones showing purple veins. I feel as though I'm stunting it and I'd like to do something. Any suggestions would be great.

Currently have it under two-54w 6400K fluorescents on a 16/8 schedule. Distance from bulbs is approx 4-5 inches. I turn on a fan every once in a while to get some circulation.