help

my mother plant's leaves are turning yellow then brown can't figure it out. the nutrients that I am using are flora nova,lyquid karma,and silica blast the plant is potted in coco fiber I test my ph every time and I make new water every three days. temp seems fine. Its growing rapid but some of the leaves are turning colours, I don't get it, please help:wtf:

Fill out the troubleshooting form in my sig and post some pics if you can, there isn't enough info to know much of anything.

ill post some pictures later this evening when I can barrow a camera. thanks again:detective1: