I usually fill my hot tub right from the pool, that way the water starts out balanced from the beginning. If filling with fresh water you can use dichlor for the first week or so then switch to bleach as the CYA level comes up to where you want it. I monitor CYA a little more closely in the hot tub, testing every couple weeks. The pool rarely changes but I have had it drop off in the hot tub. If I need to add a bit I just chlorinate with dichlor for a day or two and then back to bleach. Everything works just like the pool, it just takes very small amounts.
After each use (usually 2 people for a half hour) I add 2 ounces of bleach, if you have more people in or go for a longer time it will take a little more.
The guy at Leslie's was telling that granulated chlorine is better for Spas because of the high temp, liquid chlorine will not last as longand therefore costing you more money? Is this accurate? I have an above ground Bestway and an Elite Spas jacuzzi.