HotSpring Landmark Owner's Manual page 48

BALANCING THE CALCIUM HARDNESS (CH)
A. The recommended Calcium Hardness (CH) level for your spa is 150-200 ppm.
B. Calcium Hardness is a measure of the total amount of dissolved calcium in the water. Calcium helps control the corrosive nature of the spa's
water. That's why calcium-low water (commonly known as "soft" water) is not recommended. It is very corrosive to the equipment, and can
cause staining of the spa shell.
C. If the CH is too high (commonly known as "hard" water), formation of scale on the spa's shell surface and equipment can result. CH can be
decreased by dilution – a mixture of 75% hard and 25% soft water will be a good starting point. If soft water is not available, or practical
for you, a stain and scale control such as Hot Spring FreshWater Stain and Scale Defense should be added to the spa water, according to
instructions on its label.
D. Once the CH is balanced, it normally remains stable, although the addition of more water with a high or low calcium content will raise or lower
the CH reading of the water.
E. When the Calcium Hardness is within the recommended range, proceed to the next step.
BALANCING THE pH
A. The recommended pH level for your spa water is 7.4-7.6.
B. The pH level is the measure of acidity and alkalinity. Values above 7 are alkaline; those below
7 are acidic. Maintaining the proper pH level is extremely important for:
• Optimizing the effectiveness of the sanitizer.
• Maintaining water that is comfortable for the user.
• Preventing equipment deterioration.
C. If the spa water's pH level is too low, the following may result:
• The sanitizer will dissipate rapidly.
• The water may become irritating to spa users.
• The spa's equipment may corrode.
If the pH is too low, it can be increased by adding Hot Spring FreshWater pH/Alkalinity Up, or sodium hydrogen carbonate to the spa
water.
D. If the pH level is too high, the following may result:
• The sanitizer is less effective.
• Scale will form on the spa shell surface and the equipment.
• The water may become cloudy.
• The filter cartridge pores may become obstructed.
If the pH is too high, it can be decreased by adding Hot Spring FreshWater pH/Alkalinity Down, or sodium bisulfate to the spa water.
NOTE: After adding sodium hydrogen carbonate or sodium bisulfate, wait two hours before testing the water for pH. Measurements taken too
soon may not be accurate.
E. It is important to check the pH on a regular basis. The pH will be affected by the bather load, the addition of new water, the addition of various
chemicals, and the type of sanitizer used.
F. When the pH is within the recommended range, proceed to the final step.
Water Quality and Maintenance
Page 45
ALKALINE
ADD pH
SPA
DECREASER
WATER
TO LOWER
(SCALING
ZONE)
COMFORT
ZONE
ACIDIC
SPA
ADD pH
WATER
INCREASER
TO RAISE
(CORROSIVE
ZONE)
pH
IDEAL
pH