Calcium Hardness 4KG $24.77 Calcium Hardness 4KG quantity Add to cart Category: Pool Chemicals Related products HTH Extra Algimycin Algaecide – 1L $29.77 Add to cart Clear Blue ® Clarifier – 1L $19.77 Add to cart Excel 5-Way Pool Saver $64.77 Select options TLC® Surface Cleaner – 1L $17.77 Add to cart