when you change to flowering nutrients and you notice some yellowing try putting a layer of bat guano or worm castings across the top. When you water do not over water, watering it in will make a huge difference believe it or not. One layer can probably last 2-3 weeks, so if u do a handfull every 2 weeks i think you wont have problems like this in the flowering cycle
edit: by over water im saying dont let water go through the bottom and slowly water it so the soil sucks up the water slowly, and spreads thoroughly. It is a very basic concept but if you water your nutrients through the pot it will somewhat take out whatever you arent including with your nutrients. Some growers do a single leech 2 weeks before flower, if they are vegging over a month. This is running water through the pot to get out any salt build up from the fertilizers. it is a good practice although most experienced growers try to get the plant to full maturity before reaching the one month point. I think your gonna be fine just pay more attention to basic things like not leeching out too many nutrients and not overdosing either. Organics is nice because you can add a little and it goes a long way