Sensi skunk fem

So forgot to add last week I took out the scrog net as I personally think the plants were to far into flowering now to be trying to tie them down! This week I’ve been trying to check trichomes!! Also I’ve added canna pk13/14 nutrients! As I think there getting closer to harvest time! I’m planning on using this 13:14 for two weeks feeding?? Then flush for 7-10 days with just normal soft tap water ph’d down to 5.8!!?? Also ordered a microscope just waiting on arrival! So I need to keep checking these trichomes until turning a little milky?? But overall still happy with my first grow so far! Notice leaves are turning yellow do I trim them? Or let them die naturally? Any help still needed cheers