One advantage of the liquid is that it doesn't lower your pH as it is essentially a salt with a pH of around 8, according to the label. I opted to spring for three gallons to get my CA up quickly and reliably at start-up. Worked like a charm, getting my 20,000+ gallon pool to 40 - 50ppm by the next day (with pump running overnight). I wouldn't use it every time, but for a new pool start-up, I preferred not to risk granules laying on my fresh plaster. Besides, I was spending enough time sweeping and balancing out the general chemistry, that a few bucks for an initial short-cut seemed worth it, and I didn't want something else messing with my pH.