ive grown fond over the years of a method known as PH cycling, move it up and down during flower, not much just 0.1 at a time and keep it between 6.0-6.5 PH. dont do it every watering, water a couple times at the same PH then u can adjust it on the third, maybe like one per week, as not to shock the plants. small fluctuations in PH will allow better assimilation of different compounds. this is due to the fact that there isnt one set PH where everything is most efficiently used. some things are best available at more acidic levels and some are better available in a more base environment, cycling it ensures it will never go to long without the PH being optimal for any particular element or compound.