You CAN buy the liquid CYA which I tried this year because I had to get my CYA level up quickly. I found it at Leslies but it's pricey--nearly $40/gallon. It actually worked very well, though it looked like a disaster at first--white glop on the bottom. But I brushed it with a long handled squeegee and it ended up working nicely. Within 24 hours my CYA went from 0 to 30+ppm with 2 gallons. You must remember to shake the bottle first and don't turn off your filter for 72 hours.

As for the sock method, a stocking from panty hose works better. Still, it can take 2 days to a week to get CYA up. You CAN try to mix it into a 5 gal bucket, but don't heat the water. I've tried using a length of 2x2 to crush the granules further and while it does help, it's still a slow process. Crush, mix, pour off the milky liquid. Add more water to the remaining granules, crush, mix, pour. Repeat. Pretty labor intensive and I haven't done it in a dozen years, but it DOES speed up delivery.