Possible Deficiency? Help Needed

[Sprite]

Hello All, I'm new to The Hot Pepper Forums here and any grow forum in general. I've been growing jalapenos, Scotch Bonnets, hab's and a few thai variety over the years but never seem to master the art. Not to say I haven't had some great pickings (Guess that's what keeps us green fingered aye? and I love it). This year I am noticing that some of my seedlings & young plants are looking very different in size, shape and vigour, so I'm wondering if anyone can put their finger on it and give me some help or a few tips maybe. Will be transplanting to new size pots very soon. So a little on what I have to show and what I've done so far:
 
 
Red Habanero Maya Pic 1: https://imgur.com/VWRgWQQ
 
Red Habanero Maya Pic 2: https://imgur.com/WQaHFTV
 
Red Habanero Maya Pic 3: https://imgur.com/ToWCQyD
 
 
 
Photos are a little dark so sorry about that. As you can see, Pic 1 is what I'd expect them to look like give or take at this stage from germination up untill now. The other 2 pics are the same seed stock from the same packet, start the same time and are all in the same style containers with same soil and watered when they need it at the same time etc. They have been started under T5 lighting not to close and with a small breeze over the tops, but cannot work out why pics 2+3 show what looks like to me a possible deficiency or human error? Am I worrying about nothing? Could it be incorrect watering at some point down the line? I have to ask as over the years I've made some silly mistakes like germinating in JI. 3 soil, over watering and stunting the hell out of plant's only to realise that that was a no..no. So can anyone here help old Sprite? :0)
 
Thanks for reading and having a look at me post, look forwards to some help
 

 

[Sprite]

Forgot to mention they were all started in seedling compost with a small amount of perlite and vermiculite, and have just started to give them a little food + calcium in their filter water @ a ph of roughly 6.3 -6.5 as they were looking a little hungry.

 

[Chilidude]

Too many growing in the same container, so they are just running out of nutrients, you better re-pot them in separate containers soon as possible.

 

[Sprite]

Thanks Chillidude, thought it may be something as simple as human error but why the big difference? guess the seedlings in pic one were just stronger. Anyhow will re-pot in morning. Thanks for your input man. 

 

[willard3]

Post fotos, not links.