Excuse the n00b questions here, you'll have to forgive me.
Unknown strain here was passed to me in a bag of Bio Bizz and sprouted pretty unexpectedly.

Plant is about 2 1/2 weeks out of it seed and was doing nicely. Soon after topping the lower leaves got what looked like an NK problem.

Any help appreciated here.

seeds and seedlings dont need any plant food, just water, i would give them a good leaching, or transplant into potting soil.

definitly too hot , weird cas i start all my seeds and clones in allmix and never have a problem , i wouldnt feed em anything but water like grandad said but id leave em in the allmix after youve put a bit of water through the pots

Thanks guys.
Should add that the temp never goes beyond 26c and humidity is stable at 68% (Digital read out would not display on the photographs I took).