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2016-0685
2017-10-02
If SI > 0, Scaling or cloudy water condition.
If SI < 0, Corrosive to metals or eye & skin irritating condition.
The SI is considered satisfactory if the value is within -0.3 to +0.3 range. Zero being perfect.
SPA Water Adjustment
How to adjust the spa water chemistry when the levels are off the range.
CAUTION:
Always follow the chemical manufacturer’s directions, and the health and hazard
warnings.
Total Alkalinity (TA) Adjustment
Remove the spa cover to aerate the water and use the included test strips to check the
chemistry level. Ensure the chlorine level in the water is between 3-5 ppm first, as
chlorine will affect the TA test result.
If the TA level (and not the pH) is higher than 120 ppm, to lower the TA level, you add muriatic
acid (hydrochloric acid) or sodium bisulfate.
If the TA level is lower than 60 ppm, you add sodium bicarbonate.
For
example (for 4 adults), if the
TA level is 180 ppm, the desired decrease is 60 ppm, from
below chart, you need to add 121 g (0.269 Lb) of sodium bisulfate or 96 ml (0.101 qt) of muriatic
acid.
If the test strip color is between 180 ppm and 240 ppm, and close to 180 ppm, you can also
add 121 g (0.269 Lb) of sodium bisulfate or 96 ml (0.101 qt) of muriatic acid.
If the reading is more than 240 ppm, you can add sodium bisulfate or muriatic acid to the water
drop by drop until the test strip indicates a 240 ppm reading, then add 238 g (0.528 Lb) of
sodium bisulfate or 192 ml (0.202 qt) of muriatic acid.
NOTE:
After adjustment, retest the water after 24 hours and adjust again if necessary.
Lowering Total Alkalinity
Amount of Sodium Bisulfate to lower Total Alkalinity
Desired level
60 ppm
80 ppm
100 ppm
120 ppm
140 ppm
Volume:
795 L / 210 gal
121 g
161 g
202 g
238 g
283 g
0.269 Lb
0.358 Lb
0.448 Lb
0.528 Lb
0.627 Lb
Volume:
1098 L / 290 gal
168 g
224 g
279 g
335 g
391 g
0.368 Lb
0.492 Lb
0.614 Lb
0.737 Lb
0.860 Lb
Amount of Muriatic Acid to lower Total Alkalinity
Desired Level
60 ppm
80 ppm
100 ppm
120 ppm
140 ppm
Volume: 210
96 mL
128 mL
160 mL
192 mL
223 mL