Bob Lowry Breaks Down the Most Powerful Chlorine for Pools
Chlorine gets marketed with big numbers, and those numbers often create more confusion than clarity. Pool owners and even many pros hear that liquid chlorine is “weak” because it might say 10% or 12.5%, while trichlor tablets can claim 90% or 99% available chlorine. The key is learning what those percentages actually describe and how they’re measured. Some labels reflect weight-to-weight concentration, others use trade percent conventions, and liquids introduce volume-based assumptions that don’t map cleanly onto dry products. A practical comparison cuts through the noise: a gallon of 12.5% sodium hypochlorite delivers about one pound of pure chlorine equivalent, while a pound of trichlor delivers roughly 0.9 pounds of chlorine equivalent. Once you translate products into “pounds of available chlorine delivered,” the strongest chlorine type becomes a math question, not a branding contest, and you can dose accurately for pool sanitation and water chemistry control. A bi...