Step one: make ro/di water
Step two: add kalk and stir (anywhere up to 3tsp per gallon)
Step three: cover and wait until clear (overnight)
Step four: drip in tank
Precautions - make sure your drip can't open up. Accidental kalk overdose can result in total death from pH spike (worst) or snowstorm (not so bad).
I have about 120 total gallons, and keep about 5 gallons of kalk in the topoff. Even if all 5 gallons pumped in, I'd only have a slight snowstorm.