Hasa Hi-Temp Eco-Safe Spa Clarifier Causes Tiny Particles Of Debris In Spa Water To Coagulate (Join Together) So That They May Be Readily Removed From The Water By The Filter. The Brilliance And Clarity Of Spa Water Depend On The Efficient Activity Of The Filter As Well As The Chemicals Used To Sanitize The Water. It Is Recommended That Your Filter Cartridge Or Element Be Cleaned In Hasa Hi-Temp Spa Filter Soak On A Routine Basis, Frequency Depending Upon The Use Of The Spa. Hasa Hi-Temp Spa Clarifier May Be Used In Any Fiberglass, Vinyl, Plaster, Tile, Or Acrylic Spa. Quart Size.