Any help would be really appreciated..

Hello guys, let me get strait to the point.

Great white shark(GHS), 4th week from seed
250w aircooled hps, 12 cm above the top
temp never exceeds 26 celcius,humidity around 50%
all mix soil (biobizz)
the last 2 waterings with bio grow(at 0,7 ec), didnt start them sooner because i know all mix is pretty strong,i started em when i saw some yellow on the tips of the older fan leaves

When i water the plant i use some apple vinegar to lower the ph to 6.5( after ive added the nutes)

I also measured the drainage water and it seems to be at ~7ph & the ec is at 1~1,1

Check the pics & enlighten me cause i ve got no idea on what im doing wrong. Thanks in advance for the answers..

dont get me wrong, i ve done my reading & it seems to me that its cal(or mn) defiecincy but i dont know if its a deficiency or a lockdown & i certainly dont know the way to properly deal with it :S