I'm not familiar with "aqua flake a+b"... All I can say is that when your in flower the plant is trying to produce buds and resin... you wanna make damn sure that your lady has everything she could want so all she has to do is create for you. If "aqua flake" is a complete nutrient with all your micro and macro nutrients, then you should be fine just adding some p/k booster into your feed program. I can't say if you should be using more nutes, but if she is healthy then you shouldn't have to make any big changes.
The trimming your talking about is referred to as "lollipopping", where you basically strip the branches on the bottom half of your plant. Essentially, this is all about "light penetration". You want to take off anything that your light cannot penetrate to. This should make the bud sites that you leave grow into bigger, fuller buds.
Hope this helps.