Strange lime green plant

Soil promix 3 week old seedling
2 ml per liter advanced sensi ab.2 ml voodoo juice 2 ml b52
Was a weak seedling.

From the pic, it seems 2 others are showing issues as well. What is your ph of water going in?

It's coming out of the tap around 7 the nutrients I'm using say they are ph perfect I checked the mixed nutes a few weeks ago and they read
6.3 .to be honest I haven't checked since

Heres a photo of the rest

That's alot of plants, but many of them seem to be showing or starting the same issue. I have never used the sensi line, so it's hard to comment on it, but i was thinking at first that the ph is too high and causing a lockout of heavier elements, namely iron, and/or, possible sulfur lacking. You have some purple veins on a few, which is usually not due to genetics, but either a lack of phosphorus, or magnesium to carry the phosphorus. I use pro mix as well...for me, i found 6.0-6.2 to be best..higher up, i had issues as well with tops.

Thanks I'm gonna check my ph
The purple stems are genetic .the're
Og#18

At least I'm pretty sure its genetic