I think my plants is dying but i cant figure out whats wrong with it

so i recently got a strain called 5x kush from a friend.it's in foxfarm ocean forest soil and was doing well under a 400watt hps light.it's been in 12/12 and has grown quite a bit since i got it about 2 weeks ago, but about 3 days ago some of the leaves started turning yellow and now have brownish gray spots on them.the tips of the leaves also appear to be burning.it's currently in a grow box wit a couple of other plants and this seems to be the only plant it's happening to.i water it daily with botanicare puregrow nutrients.i have no clue what could be wrong.was really looking forward to harvesting & smoking this strain and don't want it to die when im so close to doing so.really need help

You are watering daily?

What size pot is this plant in?

If you are using soil then you dont normally feed every time you water unless you are feeding at a VERY REDUCED rate of nutrients.


In order to successfully diagnose your plants we are going to need a pic of the effected area and a whole plant pic to see whats happening.



J