I always just get the diamond grinder from work(takes about 15 mins to do an average 2 car garage floor), acid wash, rinse, let dry, check for moisture with plastic overnight and apply sherwin williams epoxy. Have never had a floor fail. Floors typically faile either because the epoxy was applied over something that it could not adhere to(could be a drop of oil or anything which could cause a void in the seal), or the concrete wasnt tested for moisture prior to applying causing in a lack of seal or breaking of the seal.