@nivek
there are a few approaches..
don't worry - one of my favorite methods. the majority are successful with it.
worry but do nothing - also works freakishly well.
now the actively worry..
mix 3 - 5 gallon at a time - easiest approach. simply averages the mix out. requires stirring between feeds. works great.
pulverize / blend - kind of a method du jour. way too involved for my level of lazy. if you have a larger bag you can take a few cups out at a time to blend it up. makes stuff a bit easier to do.
what i do..
zap and go - i feed by grams / gallon (liter). i pre measure and pre mix in a small jar with a little feed water.. makes the stuff easy to shake up. i will zap the jar in the mic - lid off - and then give it another shake or two after. melts out any of the silly calcium balls and reduces precipitate. add immediately to the rest of the feed water and stir / ph / feed.
other suggestions...
i bought a larger bag, poured in to another container, then divided it up in to smaller ones for easier handling and storage. it helped mix the calcium balls evenly through. it also helps keep moisture out of the mc.