Auto AK47 First time grow.. need advice seem to be really stunted..

Hey guys, I have 5 ak 47 autos going in about 40 litres of water with 4 airstones and a drip system,its been 10 days and I feel like they should be bigger am I wrong..? here are some pictures..

10 days from planting of the seed or from sprouting?

10 days from planting of the seed.. the two small ones seem to have just stopped growing.

Are they from Female? I just finished a run of Female Ak and Female Auto bubble. They were all different phenos. 1 of the AK was a Hermie and I ended up getting seeds out of both strains. I almost threw 1 of the Ak and 1 of the Bubbles away cause they just didn't grow right. The bubble I was gonna pitch ended up yielding over a qp dry of shit IMO. I ended up just making bubble hash out of it. The AK's ended up above average but the bubbles suck. I grew mine in coco so I can't be much help with your system but I can tell you that I had some similar experiences. My best AK started as the runt but finished strong. What is your ph?

I must admit that after this past run of auto's I can say I am over them. It's easier, just as fast, cheaper and I yield more from clones.