anyone with GDP experience?

Hello all you green wizards out there!!

I have a couple (2) Grandaddy Purples going for the second time and i can't seem to get a hold on them. They always look great until about week 2 or 3 of flower and then they get crispy leaf tip, and very droopy leaves.

I am not so much looking for a diagnosis as i am some general tips on growing the strain. Its possible i went a little heavy feeding them in the beginning. I flushed after and gave them some delicious microbial TEA so i thought they would come around. Are they VERY light feeders? Or maybe heavy feeders?

Any kahnowledge and or techniques to grow this strain properly would be so very appreciated.:thumbsup:

all rolls in to one