Calcium Hardness – 4KG $24.77 24 in stock Calcium Hardness - 4KG quantity Add to cart SKU: 72216 Category: Pool Chemicals Related products Pool Opening Kit $49.77 Add to cart Oxy-Out – 7KG $69.77 Add to cart Pool Closing Kit – up to 100,000L $49.77 Read more C-Clear – 1L $21.77 Add to cart