BioGuard Kleen It 1 Qt. | Pool Filter Cleaner

BioGuard Kleen It is an acidic filter cleaner that dissolves the mineral side of filter fouling — scale, rust, metal deposits, and hardened clarifier residue that no amount of rinsing or backwashing will remove. Filter media gets dirty in two fundamentally different ways, and this is the distinction most pool owners never learn. One kind of fouling is organic: body oils, sunscreen, lotions, and the greasy film they leave behind. The other is mineral: calcium scale precipitating out of hard water, iron and copper depositing from fill water or corroding equipment, and clarifier residue building into a crust. Those two require completely different chemistry to remove. A degreaser will not dissolve calcium. An acid will not lift oil. Kleen It handles the mineral half. At a pH of 1.0 it's a genuine acid cleaner, strong enough to break apart scale that has been building for seasons and release metal staining from filter media — while still being safe on the filter equipment itself, across sand, cartridge, and DE systems alike. It works by spray or by soak, so you can do a quick maintenance clean in fifteen minutes or run an overnight soak on elements that have been neglected. The payoff is measured in flow. Scale on filter media restricts water passage the same way it restricts a heater element, which drives operating pressure up, shortens filter cycles, forces the pump to work harder, and quietly reduces how much water actually gets filtered per day. Clearing it brings pressure back toward baseline and returns the filter to the performance it had when it was new. Used once or twice a season, it meaningfully extends the working life of the media — and a cartridge set costs considerably more than a bottle of cleaner. It also works beyond the filter. The same formula cleans spa surfaces, pool equipment, outdoor furniture, and vinyl, plastic, and rubber surfaces, and it carries a fresh citrus scent rather than the sharp acid smell you'd expect. Pro Tip: A truly dirty filter needs two cleaners, in this order: degrease first, descale second. Strip the oil and grease with BioGuard Strip-Kwik, rinse thoroughly, then treat with Kleen It for scale and metals. Doing it in reverse wastes the acid, because it can't reach mineral deposits through a coating of body oil. Never mix the two products or combine them in the same soak — run them as separate steps with a complete rinse between. Most cartridges people write off as worn out were only ever getting half of a two-part cleaning. Brand BioGuard®