on the 29th, the guys are coming in to finish up my pool project (wiring, heater install, connect the swg and new pump)

when we are ready to fire up the system that afternoon, i'd like to be able to have the pool pre-salted so i'm ready to go. how soon before should i dump in and disperse the salt with a brush around the pool , how long should i run the pump to get it dissolved.

also, if someone can restate the specs on the salt? i am planning to get water softener salt but i want to make sure i have the right minimum whatever the specs are for purity before i buy..and what it should not include.(i.e. that yellow stuff that has been talked about)

ps- re: salt dissolve, my pool is 12,000 gallons or so starting with a ppm of about 400 if that has any bearing on dissolve rate and time needed. thanks again.