Inground Spas
LTR20121002, Rev. A
Clear Water Plan
www. c a l s p a s . c o m
31
Testing and Adjusting Spa Water
You have two types of testing methods to choose from:
The • reagent test kit is a method which provides a high level of accuracy. It is available in either liquid
or tablet form.
Test strips • are a convenient testing method commonly used by spa owners.
Balancing the pH
The pH level is the measure of the balance between
acidity and alkalinity.
If the pH is too low, it can cause corrosion of metal x-
tures and the heating element. Low pH can be corrected
by adding a pH-alkalinity increaser.
If the pH is too high, it can cause scaling by allowing
metals or minerals to form deposits and stain spa sur-
faces. High pH can be corrected by adding a pH-alkalin-
ity decreaser.
8.2
8.0
7.8
7.6
7.4
7.2
7.0
6.8
6.6
Too alkaline,
causes scaling
Ideal balance
Too acidic,
causes corrosion
Need to lower the pH level
Need to raise the pH level
Balancing the Total Alkalinity
Total alkalinity (TA) is the measure of the total lev-
els of carbonates, bicarbonates, hydroxides, and
other alkaline substances in the water. TA can be
considered a “pH buffer”. It is the measure of the
ability of the water to resist changes in pH level.
The recommended total alkalinity is 80 - 120
ppm.
If the TA is too low, the pH level will uctuate wide-
ly from high to low. Low TA can be corrected by
adding a pH-alkalinity increaser.
If the TA is too high, the pH level will tend to be
too high and may be difcult to bring down. High
TA can be corrected by adding a pH-alkalinity de-
creaser.
When the TA is balanced, it normally remains sta-
ble, although adding water with high or low alkalin-
ity will raise or lower the TA level.
Balancing the Calcium Hardness
Calcium hardness (CH) is a measure of the total
amount of dissolved calcium in the water. Calcium
helps control the corrosive nature of the spa’s wa-
ter and is why soft water is not recommended. The
low calcium content of soft water is very corrosive
to the equipment and can cause staining of the spa
shell.
The recommended calcium hardness is 150
- 200 ppm.
If the CH is too low, add a calcium hardness in-
creaser.
If the CH is too high, dilute the spa water with soft
water.
When the CH is balanced, it normally remains sta-
ble, although adding soft water or very hard water
will raise or lower the CH level.
Testing For: Ideal Range (ppm)
Minimum Maximum
Total Alkalinity 80 120
Calcium Hardness 150 200
pH 7.4 7.6