347
A
S AVE THESE INSTRUCTIONS
(347IO) SPA ENGLISH 7.5” X 10.3” PANTONE 295U 07/08/2020
English
Page 19
SPA WATER CHEMISTRY AND BALANCE
Parameter
Value
a
Water clarity
clear view of the bottom
Total Alkalinity (TA) in mg/l
60 to 120
Calcium Hardness (CaCO
3
) in mg/l
150 to 250
Colour of the water
no colour should be observed
b, c
Turbidity in FNU/NTU
max. 1.5
(preferably less than 0.5)
Nitrate concentration above that of fill water in mg/l
max. difference of 20 compared
to the fill water concentration
Total organic carbon (TOC) in mg/l
d
max. 4.0
Redox potential against Ag/AgCI 3.5 M KCl in mV
min. 650
pH value
e, f
6.8 to 7.6
Free active chlorine (without cyanuric acid) in mg/l
0.3 to 1.5
g
Bromine in mg/l
2.0 to 4.0
h
When using alternative/additional disinfectants other appropriate parameters may be considered.
a
Consult national regulations and guidelines for any deviations.
b Natural water sources may introduce water colouration.
c Intentional water colouration is excluded.
d When using organic compounds this value may be higher.
e
Subject to the flocculant(s) used (if any).
f
When pH is greater than 7.5 the free active chlorine is less than 50 %.
g
Commonly recommended concentration of free chlorine in aquatic settings is 0.3 to 1.5 mg/l. However,
in order to ensure water hygiene in the spa setting where the water is heated and the water volume to
user ratio is low, it is acceptable to temporarily exceed this concentration with manual dosage, provided
the health of the user is not compromised. Therefore, a range of 2.0 to 4.0 mg/l is acceptable as also
recommended by the U.S. Environmental Protection Agency and the Center for Disease Control. Do not
use cyanuric acid.
h Temporary exceeding due to manual dosage and low water volume to user ratio is acceptable, provided
the health of the user is not compromised.
Particular care should be taken with chemical treatment of the water with special attention to disinfectant limits
and control of pH values. The use of ozone or UV, where applicable, shall always be accompanied by residual
disinfection with an oxidising biocide (e.g. Chlorine or Bromine or other biocide products, compatible with
manufacturer’s recommendations).
Improper use of chemicals may result in degradation, damage and other imperfections of the spa surface and
other spa components (typically discolouration of materials, corrosion of metal parts).
Free chlorine:
is the chlorine residual present in the spa water.
Result if too low – Inadequate level of disinfection.
Result if too high – cause odor problem, skin & eye irritation, corroded metals and other materials.
pH:
a value that indicates how acidic or basic the spa water is.
Result if too low – Corroded metals, eye & skin irritation, and destruction of total alkalinity.
Result if too high – Scale formation, cloudy water, shorter filter/heater runs, eye & skin irritation, poor chlorine
efficiency.
Total Alkalinity (TA):
indicates the degree of the water’s resistance to pH change. It determines the speed
and ease of pH change, so always adjust total alkalinity before adjusting the pH level.
Result if too low – Corroded metals, eye & skin irritation. Low alkalinity will cause the pH to be unstable.
Result if too high – Scale formation, cloudy water, shorter filter/heater runs, eye & skin irritation, high chlorine
demand.
