What is Water Scale?

Scale is more commonly known as hard water. This is caused by high concentrations of calcium, magnesium, and other metallic elements. This is commonly seen when clear drinking glasses turn white and spotty from being washed or white crust forms on the sink faucet. This can also affect your spa by creating a crust in your spa’s plumbing & heater or forming a sandpaper feeling layer on the seats.

There are general guidelines listed by the United States Geological Survey to determine if you have hard water. If you test your water for hardness with a test strip and the result is between 0-60 mg/L you have soft water. If the result is between 61-120 mg/L your water is considered moderately hard. A result between 121-180 mg/L is considered hard and if it’s greater than 180 mg/L its considered extremely hard.

What Does Stain and Scale Control Do?

SpaGuard’s Stain and Scale Control enables spa owners to prevent stains caused by iron (red/brown tint), copper (green tint) and manganese (brownish red), as well as scaling caused by a high level of calcium.

Scaling can occur with high calcium hardness, high water temperatures and/or high pH. The minerals drop out of the water and rough, sandpaper textured, spots appear on the spa surfaces, circulation and filtration systems and heaters.


At Initial fill and each time your refill:

  • Turn on all jets
  • Add 1 fluid oz (2 tablespoons or 4 cap-fulls) of Stain & Scale Control per 300 gallons of water
  • Test water to determine pH levels
  • Adjust Alkalinity to (100-150 ppm)
  • Adjust pH as needed to maintain in appropriate range (7.2-7.6)



  • Turn on all pumps
  • Add 1 fluid oz (2 tablespoons or 4 cap-fulls) of Stain & Scale Control per 300 gallons of water weekly to gradually remove scale from surfaces
  • Use a soft sponge to clean the spa surface at the water line
  • Test water to determine the spa water’s alkalinity level
  •  Adjust alkalinity into the correct range (100-150 ppm) with either pH decreaser (lowers alkalinity) or Alkalinity increaser as needed.
  • Test water to determine the spa water’s pH levels
  • Add pH Decreaser if pH is high or pH Increaser if pH is low to maintain a pH of 7.2 – 7.6
    • This is essential as improper pH balance will cause damage to your spa and reduce the effectiveness of this product.
  • Ensure you clean all of your spa’s filters thoroughly with a garden hose and then SpaGuard Filter cleaner.
    • This is essential for using this product as the minerals will be trapped in the filter so they don’t attach to the spa’s shell.

Additional information

Weight 1.25 lbs
Dimensions 2.4 × 2.4 × 7.5 in
Spa Chemical System


SpaGuard Stain and Scale Control – 1 Quart


74 in stock

Deliver Every:

74 in stock

SKU 42644BIO Category

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