Agree with admin.
I personally mix a batch every time I feed. I mix small quantities (1LT) at a time, based on my container sizes. I know its more effort and mixing really small ratios, but I can adjust every time I feed.
I use a small 5ml syringe to measure 0.5ml,lol
Its seems to be working for me.
Interested to find various techniques for mixing nutrient solutions.