Why don't you just mix what you need for feeding when you need it? You don't have to mix a gallon every time...I use a gallon every couple days it allows it to keep better an yes I am sure it may help with my microbial activity.
I aerated my GO nutes last night for feed in the morning and I also put some of grandma's molasses and come back to see foam, so I'm gonna guess it does help with microbial life, foam is an indicator of proteins coming from the bacterias correct? I have a N deficiency more than a week into flower, does anyone know a good ratio of grow and bloom nutes to feed without giving to much N