Help!!! Determining which deficiency is this...

Hi Guys, been growing this silver haze #9 for 76 days and she has flowered 7 days ago.
She's showing some yellowing in the leaves sometimes even brownish... I took a picture from a very small black fly that showed up is it a problem?
Been feeding once a week only with liquid karma and hygrozime, i gave bat guano (0.5-12-0.5) five times and using a 12,5% sunshine mix, 12,5% coco fiber, 25% humus and 50% perlite.

Check the attached pictures to see how the leaves I'm talking about looks like.

Thanks in advance!!

Burnt tips = nute burn other then that look great

plants look almost perfect besides a little burn. leave them alone and keep doing exactly what you are doing.