Trichlor Shock in a 15,000-Gallon Pool When CYA Is Already at 70 ppm

When your CYA is already at 70 ppm, using trichlor shock can push stabilizer into a range where chlorine barely works. This post walks through the exact dose for a 15,000-gallon above-ground pool, why CYA level changes the math, and what product to reach for instead.
