The AquaFinesse SpaClean Puck is a concentrated puck of AquaFinesse that dissolves quickly to begin removal of the biofilm that is the root cause of so many spa & hot tub water problems: cloudy water, odours, bacterial build-up, clogged filters, & more. Perfect for use in spas that have been prone to chronic cloudy water, odours, and "slippery" surfaces. Easy to use - just drop the AquaFinesse SpaClean Puck into the spa or the spa's filter area 24 hours before you plan to drain & refill your spa. Allow spa to run continuously (lower the heat to minimum.) Effective - AquaFinesse SpaClean Puck thoroughly removes biofilm build-up in spa & hot tub plumbing lines, from cartridge filters & spa surfaces. More effective than other "spa flush" products. Compatible with ALL spa care systems. Eco-friendly - AquaFinesse SpaClean Puck contains no harsh chemicals. Spa water is able to be drained into almost any environment without fear of harming plants or animals.