New Grower Polo's not so happy plant! Help needed

[Teacher]

like the mudman tells ya..ph or p issue probably combo of both..watch it spread fast as the leaves yellow and mottle..flush flush check ph in and out

 

[Polo]

It has not spread at all since popping up. Not sure what the deal was; my friend(has 10years+ of normal photo plant growing exp) thought maybe heat burn since my lights were pretty low; I have since lifted them up to 45cm. I'll be going out and buying some cal-mag, P tomorrow and another fan to help with the air circulation. Thanks for the help!