A non-Division 5.1 Oxidizer tablet consisting essentially of a blend of hydrated calcium hypochlorite with magnesium sulfate heptahydrate, wherein the blend contains at least about 17% by weight of water based on the total weight of the blend; contains from about 0.1% to about 10% of lime based on the total weight of the hydrated calcium hypochlorate and magnesium sulfate heptahydrate and the average dissolving rate of the tablet is less than 150 grams per day.