BioGuard Burnout 3 1 lb. | Cal Hypo Pool Shock

BioGuard Burnout 3 is a calcium hypochlorite shock that does three jobs in one application — shocks, oxidizes, and clarifies — at 57.8% available chlorine. It's Step 2 of the BioGuard 3-Step Care System, and it's built around one property that separates it from every other shock on the shelf.

Burnout 3 is unstabilized. It contains no cyanuric acid and contributes none to the pool. That sounds like a technicality until you understand what stabilizer does over a season. Every dichlor-based shock and every trichlor tablet permanently adds cyanuric acid to the water, and cyanuric acid never evaporates, burns off, or filters out. Once it climbs high enough, free chlorine becomes progressively less effective at the same test reading — the pool looks properly chlorinated on a strip and behaves like it isn't. Owners hit this in August, wonder why their pool "stopped holding chlorine," and add more product to a problem more product can't fix.

A cal hypo shock sidesteps that entirely. You get a strong dose of oxidizing chlorine with nothing accumulating behind it, which makes Burnout 3 the right choice on any pool already carrying a high stabilizer level — and a sensible weekly default on a pool fed by trichlor tablets, since the tablets are already supplying all the cyanuric acid the water needs.

The formula dissolves quickly and, in most conditions, needs no pre-dissolving. It's suitable for vinyl and plaster pools and compatible with both chlorine and bromine sanitizer programs. It also arrives pre-measured in 1 lb bags, which removes the guesswork from dosing and keeps unused product sealed rather than absorbing moisture in an opened bucket.