Is your carpet 3-5 years old? Have you noticed it getting dirtier faster between cleanings?
When a carpet, such as Nylon, is produced in a carpet mill it is treated with a special Stain Blocker (acid dye resistor). Stain blockers are the heart of the advanced generation technology. They can best be described as large colorless dye molecules that are applied at the mill, making the fiber less susceptible to attachment of food dyes commonly found in artificially colored foods and beverages.
This stain blocker will last 3-5 years before it starts to wear off from foot traffic and normal vacuuming. At this point it becomes necessary to apply a carpet protector to the heavy traffic areas of the carpet to maintain stain resistance and longevity.