Calmag deficiency in seedlings planted in coco?

Hi guys I’m having some issues with super slow growth on my seedlings. I’m on day 17 and I feel like they’re growing at a wayyyy too slow pace.

I suspect there is some calmag deficiency in place. Attached are pics of some problematic seedlings. A few of them look fine and healthy but these are the ones that kind of looksad.

When I first transplanted these babies into coco I noticed that the runoff PPM was a whopping 1460 and PH 7.0 so I flushed them with water phed to 6.2 dosed with 2ML Athena cleanse. Now I’ve been feeding them 350 PPM of CaMg, Grow A&B. I made the newb mistake of not testing the runoff of the Coco bricks BEFORE transplanting, which were marketed as being prebuffered and triple washed of all salts.

any input?

I wish I could be more help, but, I'm not a coco grower. They appear small for 17 days and quite stretched. I would guess your lights are hung a little too high/underpowered. Also, those plants are quite young to have been transplanted already, may I ask why? I hope a coco grower or someone with more experience than I chimes in for you.

Always buffer your buffered coco,they look fine just let the roots grow.As said above stretch a little but dont drop a big light on them yet.