A little help please

Hi guys, could you tell me what deficiency this is please

With no other info and by looking at the pic I would say best guess is a Nitrogen deficiency ?

I agree looks like it is lacking nitrogen, but when the leaf stems start turning purple it can be a sign of cal/mag deficiency. If its a nitrogen def the lower leaves will start to turn completely yellow, if it's cal/mag you might see some random yellow spotting and it won't just be on the lower leaves.

its a bit of both majek i got a bottle of cal/mag and used it last night so i give it a couple days to see if all has been sorted. and i increased the amount of nitrogen also.
i just fort i should ask other people to see if i was on the right path.

thanks guys

Yes it doesnt have a plant attached to it (the leaf) and thats a deficiency. Just kidding it looks like N, can you show the whole plant?

yea sure. it kinda hard to notice in a pic plus da HPS light creates them lines but here is a link with my grow week by week

https://www.rollitup.org/newbie-central/611082-hey-you-yea-you-come.html if it dont work check out my profile and its all in the albums