Amateur grow

While it's been boring and slow for me and my family. My young ladies have not stopped and daily you can see the weight gain on the buds. So roughly 4 weeks to go and I can see a very good harvest coming ... New seeds ordered so will be preparing to get them started next week. One question. I noticed the leaves are changing yellow at bottom and I expect that. But some round the top cola on the brain damage have changed too. I am using a small tent and have kept plants as low as I could. Someone one said it could be bleaching from light as pH, temp and humidity all good. Only fed molasses now and all seems ok expect for few top fan leafs... Any advise would be taken on board ..