5 to 6 weeks into flowering...DYING LEAFS YELLOWING AND SPOT PROBLEMS !!HELP!!

so if anything when im looking for blooming nutes make sure the lower the numbers the better ?....and is it worth adding it to my plant with a month left off flowering?

Yes its worth it w a month left....the last month is a very important time...this is when ur buds mature

for NPK - the system works like N is the first number P the 2nd and K the 3rd ?....and whats the K stand for i know nitrogen and potassiam i heard the 3rd was something called potash so im not understanding K

am i right about this ?