My First Auto Grow, Need Help/advice

[KMProp]

Started me some Big Budda Critical Mass around 2 week ago, the majority seem to be coming on quite well but one seems to be a runt..?

Here are some pics and my specs, tell me what you guys think And were I'm going wrong.

Canna Coco and pebble mix 70/30
Top Fed Dripper system (to waste)
20L smart Pots
2 400W HPS (currently only have one on)
6" RAM inline (extracting)
5" RAM inline (fresh air)
120cm X 240cm X 200cm Mylar Tent


#1 (Runt)

#2

#3

#4

 

[KMProp]

Photos were taken 21st June so i shall upload a new next week as this is my first grow diary:D

 

[mothhhawk]

I had a runt in my crop, was so far behind the others. Turned out to be the biggest and the best, and had most buds too, got 110g dry off it. And it was outdoor. Was only meant to get 30-50g. :)