Pamphlet - Example Shorter Work
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Introduction
Congratulations for deciding on NOVOBLUE™ as your water testing solution of choice!
Water chemistry is a fascinating science which involves accurate and demanding attention to
detail. Nevertheless, your NOVOBLUE™ testing strips are designed to give you all the tools
that you may need to accurately understand what your water is doing – without any of the
usual testing headaches seen in many other products. Armed with the accurate information
contained herein, you will be in a strong position to treat your water effectively so that it is
safe for drinking, and sparklingly fresh and clear for bathing.
What You Will Find in This Pamphlet
In this pamphlet you will find each test parameter in its own brief section. Each section
contains a table that conveniently summarizes the most important information that a typical
home tester might need to know in order to take appropriate action. In addition to the handy
tables of information, you will find a brief discussion of any other interesting and relevant
details – things discussed typically include descriptions of why a certain substance is needed
or unsafe, as well as an explanation of how these substances may have gotten into your pool
or drinking water in the first place.
In general, our discussions of each parameter explore drinking water issues and pool/spa
operational issues separately where appropriate. A swimming pool has different demands to
drinking water in terms of high-volume public use and safety. Drinking water, on the other
hand, is consumed in far larger amounts internally than is pool/spa water as such regulations
tend to be far stricter for drinking water systems than for pools. Finally, the relatively
complex issue of pool maintenance chemistry and drinking water disinfection comes with its
own set of appropriate standards and compromises.
All information is referenced from supporting documentation (listed on the final page) and
consists of six documents containing all the data for our parameter values as well as other
miscellaneous information published by the World Health Organization (WHO), the
Environmental Protection Agency (EPA), the American National Standards Institute Inc
(ANSI), and the Association of Pool & Spa Professionals® (APSP). We encourage anyone
interested to read these fascinating resources for themselves as they contain a wealth of
interesting and important water-based information.
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Finally, we provide this information to empower our customers with the most accurate and
important information possible. This is done to enable our customers to be able to treat their
own pools/spas effectively and to make appropriate choices regarding drinking water quality
and purity.
We have gone to the utmost lengths to try to ensure that the information contained here is
accurate, up to date, and safe to implement. That being said, as in any document, there is the
possibility of error and we cannot be responsible for a misunderstanding or misapplication of
this information. We caution all our customers to consult with a professional before handling
any chemicals or treating drinking water or pool water – especially if you are inexperienced.
We wish you all the best with your water testing!
Regards,
The NOVOBLUE™ Team
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Hardness (Calcium Hardness)
POOL/SPA LEVELS
LOW:
OPTIMAL:
HIGH:
<200 mg/l
200 – 400 mg/l
>400 mg/l
DRINKING WATER LEVELS
World Health Organization:
No health-based guideline value set.
EPA:
No health-based guideline set.
The most common maximum guideline value
set by countries worldwide at the time of
printing was 500 mg/l.
This value has been set for taste purposes, to
minimize corrosion, and to minimize scale
deposits on infrastructure/household items.
Hard water is NOT harmful to health.
Most countries set targets lower than
500mg/l as “desirable” (100 – 200 mg/l).
HIGH/MAX:
OK:
OPTIMAL:
500 – 1000 mg/l
200 – 500 mg/l
100 – 200 mg/l
Hardness is a measure of the total dissolved calcium and magnesium ions in water. Usually,
tests simply measure the calcium ions in a solution, hence the test is often called a “calcium
hardness” measure. The more Calcium ions (and Magnesium ions) in water, the ‘harder’ the
water is.
The ‘hardness’ of water is not a health concern for drinking water. Hardness does affect the
taste of drinking water and can result in white scale deposits on tap-heads, shower-heads,
inside kettles, and inside hot water geysers and piping at values higher than 200 mg/l. Harder
water does not form a lather as easily as soft water and may totally resist lather formation
which would cause soaps and detergents to be less efficient. (3)
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For pools, hardness is an important measure that needs to be monitored because too high or
too low hardness can cause damage to the pool walls or fabric (etching on surfaces and
corrosion). Hardness less than 100 mg/l can be corrosive to water piping in municipal
drinking water supply systems and pool systems, whilst levels above 400 mg/l can cause scale
deposits in piping and affect filtration systems depending on the Ph. (1) (3)
pH
POOL/SPA LEVELS
W.H.O.
(Cl based disinfectant): 7.2 – 7.8
(Br based disinfectant): 7.2 – 8.0
ANSI/APSP
7.2 – 7.8
OPTIMAL: 7.2 – 7.8
DRINKING WATER LEVELS
W.H.O.
*No health-based guideline given
(Common Levels Found: 6.5 – 8.5)
EPA:
*Secondary Standard: 6.5 – 8.5
*Commonly found pH levels in water
distribution systems are not a health
concern.
EPA: pH is to be maintained in the
range 6.5 – 8.5 to enhance taste,
prevent corrosion on piping, and aid
chlorine-based disinfection.
pH is a measure of the total hydrogen ions in a solution. Another way to think about pH is
that it is a measure of how acidic a liquid is. ` Lower values of pH (<7.0) are more acidic and
higher values (>7.0) are less acidic (more “alkaline”, or “basic”). A pH reading of 7.0 is
perfectly neutral, neither acidic nor basic.
The human body tightly controls pH levels because pH affects the way chemical reactions
proceed. However, different pH levels are normal in different parts of the body. In the
stomach, for example, the presence of hydrochloric acid used to dissolve food can bring the
pH down to a value of about 2 (extremely acidic), whilst human blood has a very small range
of values that the body tightly controls ranging from 7.35 to 7.45. If blood pH drops below
7.35 then it becomes too acidic and causes major health complications – a condition known
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as acidosis. On the other hand, blood pH levels above 7.45 are also dangerously leading to an
alkaline condition known as alkalosis.
Generally speaking, the food and water we ingest have almost no effect on our pH levels.
This is because the body buffers and controls these levels so tightly. Thus, drinking water
shouldn’t affect our blood pH at all. However, ingesting water of high or low pH over long
periods of time does put a slight nutritional demand on the body to keep our buffer
compounds in good supply – any reasonably varied diet will automatically contain the
required nutrients to suit this purpose.
The main concern with pH levels in drinking water is not so much to do with health but
rather aesthetic. Taste is linked to pH, as is hardness/softness. Alkaline water (high pH) has a
distinctive taste that many people find unappealing. Extreme pH readings should obviously
always be avoided in drinking water – by analogy, we don’t want to be drinking
hydrochloric acid (stomach/pool acid) or caustic soda, nor would we bathe in such corrosive
substances – in either case, we would suffer chemical burns.
In terms of pool use, pH is very important for a few reasons. Very acidic or very basic pH
levels in pool water can be corrosive to pool machinery and irritating to the skin, eyes, and
mucous membranes. The ideal pH for nonirritating water for the eyes and skin is around 7.4
which is similar to the pH of the eyes and skin.
Another factor to consider regarding pool water is that the pH of the water affects the
chemistry of the water – particularly chlorine or disinfectant chemistry. pH values higher
than 7.5 start to decrease the effectiveness of most of the common pool chlorination
products.
The pH scale, or measure, is a logarithmic scale. This means that a small numerical difference
actually represents a massive difference in the acidity of a solution. Each 1 unit of the scale is
literally an order of magnitude of difference. This means that the difference of between say
6.0 pH and 8.0 pH is massive, 6.0 is quite acidic and 8.0 is quite basic. Any values outside this
range are notable, and people should take care in their handling of water with such pH
values.
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Total Alkalinity
POOL/SPA LEVELS
World Health Organization:
No Operational or Health Based
Guideline Given
EPA:
No Operational or Health Based
Guideline Given
ANSI/APSP:
MIN – 60 mg/l
MAX – 180 mg/l
OPTIMAL:
DRINKING WATER LEVELS
World Health Organization:
No health-based Guideline Given
EPA:
No Health Based Guideline Given
Total alkalinity is not considered a direct
health concern for drinking water. *
80 – 120 mg/l
The total alkalinity test measures how resistant water is to changes in pH. The higher the
total alkalinity the more resistant to pH changes the water will be, especially in response to
adding chlorine. Total alkalinity is usually measured as mg of calcium carbonate per liter of
water.
Keeping water pH stable when adding disinfectants is desirable. On the other hand, if the
total alkalinity is too high, then we may find it difficult to adjust pH to our liking - so we
should maintain optimal levels of carbonate for buffering our pool environments, not too
much and not too little.
ANSI/APSP sets a minimum and maximum standard of 60 mg/l and 180mg/l respectively.
Keeping carbonate levels (as calcium carbonate) between 80 mg/l and 120mg/l is considered
optimal for nearly all pool/spa environments. (1) (6)
*In terms of drinking water, no health-based guidelines are set because levels of calcium
carbonate in drinking water do not pose any health risks. However, the ability for alkaline
salts to buffer pH is still an important factor when considering how the pH of drinking water
systems can lead to corrosion of piping, especially of metals in piping. As such, stabilizing the
pH in some optimal range protects piping from being corroded and leaching metals into the
water provided the pH is in an optimal range already. The water supply authority in each
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local district will likely set some desired alkalinity according to their operational parameters
but levels will almost always be greater than 40 mg/l.
Carbonate
Unless you are a pool maintenance professional, or a professional chemist, the carbonate
measure will be as useful to your pool cleaning needs as the total alkalinity measure.
Professionals tend to need to work out carbonate levels directly so that they can calculate
what is called a “Saturation Index”. For general everyday home use, carbonate levels can be
considered to be very similar to total alkalinity. The main purpose of maintaining proper
carbonate saturation and good overall total alkalinity is to buffer water against pH changes.
Saturating water correctly also helps to reduce scale deposits and prevent corrosion.
However, if the pH is kept within optimal ranges and the total alkalinity is also kept in
optimum ranges, then in most cases a carbonate test would not be necessary.
This test is provided mostly as an extremely useful convenience for professionals in the pool
maintenance industry because it makes the computation of the LSI (saturation index) easier
to perform.
Like total alkalinity, carbonate levels have no health guideline value since they are not a
health concern. For the relevant guideline levels please refer the total alkalinity table above,
or to your own personal pool maintenance standard operations manual of choice.
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Chlorine Tests
There are two direct tests for Chlorine, “total chlorine” and “free chlorine”. These two tests
are related to each other, and both taken together can give vital information for drinking
water systems or recreational water systems.
Free Chlorine Test
POOL/SPA LEVELS
W.H.O./EPA/ANSI/APSP:
MAX:
(POOLS)
4 mg/l
(SPAS) 5 mg/l
MIN:
(POOLS)
1 mg/l
(SPAS) 2 mg/l
OPTIMAL:
As close to 1 or 2 mg/l for pools
and spas respectively.
DRINKING WATER LEVELS
W.H.O. (as Free Cl2):
MAX 5.0 mg/l
MIN 0.2 mg/l
EPA (as Free Cl2):
MAX 4.0 mg/l
Free Chlorine levels should not exceed 4
or 5 mg/l. Minimum residuals should be
at least 0.2 mg/l at the tap.
OPTIMAL:
As close as possible to 0.2 mg/l at the tap
outlet.
Chlorinated drinking water has a strong
odor and taste if levels are much higher
than 0.2 mg/l
The free chlorine test measures the amount of chlorine in your water available for
disinfection. Your free chlorine is simply the chlorine actually available to disinfect your
water because it is not bound (or combined) with other compounds - it is ‘free’ to react with
other things.
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Free chlorine present in water is often called “residual chlorine”. It is called this because after
adding chlorine in sufficient amounts there will be some fraction of the chlorine you added
which remains as free chlorine and some fraction that gets bound or used up.
This ‘residual’ is what protects your water from contamination as time passes, and is the main
reason why pools, drinking water, and stored water can remain clear for a time after adding
chlorine.
If you test for free chlorine, you are testing your residual ‘available’ chlorine. If there is some
residual chlorine present, then that means that the water you are testing will resist
contamination for as long as that residual remains present – effectively the water is sterilized
and will remain so.
Fortunately, free chlorine is toxic to microorganisms. Unfortunately, very high chlorine
levels in water can also be harmful to humans. So, there are maximum drinking water
guidelines for chlorine residuals because of this. There are also minimum guidelines for
drinking water which are set to ensure that the water is not contaminated by disease-causing
organisms. Likewise, keeping a swimming pool clean, clear, and free of microorganisms
requires similar guidelines. The optimal free chlorine values are listed in the table under the
free chlorine heading above.
Total Chlorine Test
There are no maximum guidelines for total chlorine test values. This is because this test is
mainly used to help us find out how much bound chlorine is in the water versus the amount
of free chlorine.
The total chlorine test measures all the chlorine in your water. In other words, it measures
your free chlorine (see the previous section) and your bound or combined chlorine.
Subtracting the free chlorine from the total chlorine will tell you how much chlorine is
bound to other molecules. Chlorine that is bound to other molecules is not freely available to
kill off pathogens and disinfect water. Usually, our free chlorine becomes bound because it
binds to and reacts with compounds in the water. This is why free chlorine gets used up in
the disinfection process, and also why we need to keep adding chlorine to make sure levels of
free chlorine stay high enough to keep our waters free of harmful microorganisms.
As mentioned, if we subtract the free chlorine from our measure of the total chlorine we are
left with ‘combined’ or ‘bound’ chlorine. Bound chlorine is often found in molecules called
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“chloramines” which are the molecules responsible for skin irritation, eye irritation, and the
strong obnoxious chlorine fumes commonly found around indoor pools.
The W.H.O. states that bound chlorine levels (i.e., levels of chloramines) should be no more
than half the free chlorine levels and that ideally bound chlorine levels should be kept at 0.2
mg/l or less to prevent eye irritation and strong odors in pool areas. The same levels are given
for drinking water.
How to calculate the “combined” (Bound) chlorine.
(TOTAL CHLORINE) – (FREE CHLORINE) = (BOUND CHLORINE) (as chloramines)
Below are some suggested values for bound chlorine levels to keep your pool water from
causing eye and skin irritation, and to keep drinking water from having a chlorinated odor.
**BOUND CHLORINE LEVELS (e.g., Chloramines):
POOL/SPA LEVELS
WHO:
Bound chlorine should not be
more than half the amount of
free chlorine. As little as possible
is best.
World Health Organization:
MIN:
MAX:
n/a
3 mg/l
MAX:
Optimal:
Optimal:
≤ 0.2 mg/l
EPA:
MAX:
3 mg/l
0 – 0.2 mg/l
DRINKING WATER LEVELS
EPA:
4 mg/l
OPTIMAL:
As little as possible.
MIN:
MAX:
Optimal:
n/a
4 mg/l
not given
**NOTE: Bound chlorine must be calculated from free chlorine and total chlorine. Please carefully read the
sections on free and total chlorine tests before interpreting the above table.
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Fluoride (Fl-)
POOL/SPA LEVELS
DRINKING WATER LEVELS
World Health Organization:
Fluoridation is not a relevant
issue for the operation of
pools/spas other than incidental
levels that may arise from water
sources used in the filling
process.
MAX: 1.5 mg/l (as fluoride ions)
EPA: Considered a contaminant.
MAX: 2 mg/l (as fluoride ions)
The artificial addition of Fluorine ions into drinking water supply systems has been a longtime practice in many countries. According to the World Health Organization, artificial
water fluoridation is done to ‘prevent tooth decay’. (2)
The EPA lists fluoride as a secondary water contaminant which has negative cosmetic health
effects at levels in excess of 2 mg/l. The World health organization cites the same negative
health effects but at levels 25% less (1.5 mg/l). In a global comparison of fluoride regulatory
guidelines by country, the highest ‘acceptable’ maximum guideline value set was 4 mg/l, the
lowest was 0.6 mg/l, and the most common level was set at 1.5 mg/l. (2) (3) (5)
Fluoride is found relatively often in natural sources of drinking water and contractions vary
considerably. Fluorine is also a natural component of plants and soils. Fluorine is always
found in ionic form (i.e., fluoride ions) in natural or water-based contexts.
Common health problems linked to excessive fluorine exposure include severe discoloration
of the teeth (called ‘dental fluorosis’) on the mild end. Higher concentrations lead to ever
increasingly severe health problems with the most serious complications involving severe
bone weakness and massive vulnerability to crippling bone fractures (at levels of 10 mg/l or
higher). (3)
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Cyanuric Acid (Chlorine Stabilizer)
POOL/SPA LEVELS1
00 – 30 mg/l
Low/OK
30 – 50 mg/l
Optimal
50 - 100 mg/l
OK/High
>100
Too Much
DRINKING WATER LEVELS
World Health Organization: 40 mg/l
No national regulatory values were set
by any country at the time of
publication2
Cyanuric acid (CYA) is used as a chlorine stabilizer in swimming pools. More specifically,
CYA prevents chlorine from being lost due to sunlight exposure.
Too much CYA will render chlorine ineffective (the greater the amount of CYA the less
effective your chlorine is at sterilizing your water) - the usual recommended optimum CYA
levels for pool use are between 30 and 50 mg/l.
Too little CYA in your pool means that your chlorine will degrade much more rapidly when
exposed to sunlight, making your chlorine far less efficient – you will have to add chlorine
daily in relatively large amounts to maintain your pool.
The World Health Organization has set a drinking water limit of 40mg/l. However, not a
single country has implemented any maximum regulation (so far) because CYA is considered
safe in the typical concentrations used to enhance chlorine stability.
Another reason why many countries may not have implemented a regulatory guideline for
CYA in drinking water is that CYA is not considered useful in typical municipal closed water
supply systems – it isn’t used in such systems. This is because there is almost no sunlight
exposure in a closed or piped municipal water supply network. CYA is only really useful
because it extends the longevity of free chlorine in water exposed to sunlight.
One final fact to take note of is that CYA takes very long to degrade once added to pool
water, which means that over time your CYA levels may rise. Two consequences of this fact
are that once you reach your optimal CYA levels in your pool you should stop adding any
more CYA, probably for a very long time.
The other consequence is that decreasing CYA levels in a pool that already has too much
CYA can be tricky. The most common method used to decrease CYA levels is to partially or
fully drain the pool and then refill it from a source absent of CYA – this essentially dilutes or
completely removes CYA as appropriate.
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Bromine (Bromide/Bromine ions)
POOL/SPA LEVELS1
DRINKING WATER LEVELS2 3
World Health Organization
OPTIMAL (pools):
2.0 – 2.5 mg/l (as Bromine)
(In Combo with Ozone):
15 – 20 mg/l (as bromide)
Using BCDMH
(bromochlorodimethylhydantoin)
MAX: 200 mg/l
World Health Organization:
No health-based guideline given. *
EPA:
No health-based guideline given. *
ANSI/APSP
OPTIMAL (pools):
OPTIMAL (spas):
4 – 5 mg/l**
4 – 6 mg/l**
*2 mg/l is given as a conservative
maximum value for drinking water for
children and 3 mg/l for adults.
4 mg/l
However, such high levels of bromide
in drinking water are extremely
unlikely. That is why the W.H.O. has
not set a formal or informal guideline.
**(as Bromine)
OPTIMAL:
(As total bromine)
This is presumably also the case for the
EPA which does not even discuss the
issue.
`
OPTIMAL:
< 2.2 mg/l
Extremely unlikely to find bromide
levels in drinking water anywhere
close to this value. (Less is better)
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Lead (Pb)
POOL/SPA LEVELS 1
DRINKING WATER LEVELS 2 3
World Health Organization:
MAX: 0.01 mg/l
Lead contamination is not a
relevant issue for the operation
of pools/spas other than
incidental levels that may arise
from water sources used in the
filling process.
EPA
MAX (Ideal Goal):
MAX (enforceable):
OPTIMAL:
zero
0.015
ZERO mg/l
Lead contamination of water is toxic to
human health. Ideally, we should never
drink it in any amount.
Lead is an extremely toxic metal for human health which is why such stringent controls are
in place to limit its occurrence in drinking water systems. Typically, Lead may enter
drinking water via industrial effluent, pesticides, environmental pollution, erosion of natural
lead sources, and corrosion/seepage of piping and household plumbing.
The effects of lead exposure as reported by the EPA include: Retarded or slow mental and
physical development in infants; learning disabilities and attention span deficits in young
children; and in adults, exposure can lead to kidney problems and high blood pressure.
Lead plays absolutely no useful role in any pool/spa management so levels of lead should
conform to the drinking water standards for complete safety.
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Iron (Fe)
POOL/SPA LEVELS1
Iron is not a relevant issue for
the operation of pools/spas other
than incidental levels that may
arise from water sources used in
the filling process.
High levels of iron may cause
water to be discolored and stain
pool equipment and surfaces an
orange/brown color.
DRINKING WATER LEVELS2 3
World Health Organization:
Precautionary max value: 2 mg/l*
Aesthetic MAX value:
0.2 mg/l**
Most Common value:
0.3 mg/l
*This level is not harmful to health and
is set by the W.H.O. only provisionally
as a precautionary value.
**The aesthetic maximum is given
because at levels higher than this the
taste of the water is negatively affected
and the water will stain clothing,
appliances, fixtures, and infrastructure
an unsightly orange-brown color.
EPA:
Aesthetic MAX value: 0.3mg/l***
(Secondary Contaminant guide)
***Reasoning is the same as for W.H.O.
value; please see entry (**) above.
OPTIMAL:
≤ 0.3 mg/l
Iron is very abundant in the natural environment and common levels seen in natural waters
range between 0.5 and 50 mg/l. The abundance of iron in the natural environment is the
main reason why it enters our drinking supply but it can enter our water from corroding
water pipes. Iron is needed as an essential nutrient and, depending on various factors, we
need roughly between 10 – 50 mg/day for optimum health.
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As a precaution against excessive iron exposure the W.H.O. recommends a maximum value
of 2 mg/l, however, this recommendation is only precautionary as levels of 2 mg/l are not
harmful to health.
However, Iron is not really regulated for health reasons, but rather for aesthetic reasons. Too
much iron in your pool or drinking water will tend to be a ‘brackish’ brown color and can
stain surfaces, clothing, and equipment. High levels of iron in water can taste ‘rusty’ or like
blood – most consider this unpleasant. The standard threshold for aesthetic concerns is
between 0.2 – 0.3 mg/l as recognized by the W.H.O. and the EPA.
Copper (Cu)
POOL/SPA LEVELS1
Copper is not a relevant issue for
the operation of pools/spas other
than incidental levels that may
arise from water sources used in
the filling process.
High levels of copper may cause
water to be discolored, and stain
pool equipment or surfaces
agree/blue color.
DRINKING WATER LEVELS2 3
World Health Organization:
Max value:
2.0 mg/l
Aesthetic MAX value:
1.0 mg/l*
Most Common value:
1.5 mg/l
*The aesthetic maximum is given
because at levels higher than this the
taste of the water is negatively affected
and the water will stain clothing,
appliances, fixtures, and infrastructure a
green-blue color.
EPA:
Aesthetic MAX value:
1mg/l**
(Secondary Contaminant guide)
**Reasoning the same as for W.H.O.
please see entry (*) above.
OPTIMAL:
≤ 1.0 mg/l
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Copper piping and geysers can corrode staining giving water a beautiful blue/green color.
Unfortunately, just like for iron, Copper tends to stain bathroom fittings, clothes, and walls.
At certain levels, copper lends a ‘coppery’ taste to water which many find unappealing.
The corrosion of copper piping is usually due to soft, acidic water (pH < 6.5 and hardness <
60 mg/l calcium carbonate). So, offsetting the acidity and managing the hardness of drinking
water can prevent the corrosion of copper piping.
Copper is not used in the context of pool or spa maintenance unless the piping or pump has
copper parts for aesthetic purposes – in these cases managing hardness, pH and alkalinity
should ensure the longevity of the equipment.
Nitrates & Nitrites
Nitrate (NO3−) and nitrite (NO2−) are nitrogen-containing ions that are commonly found in
water systems.
Nitrates are found naturally in the environment in plentiful supply. Nitrates are an
important nutrient for plants and are an integral part of the nitrogen cycle. Surface water
runoff can bring nitrogen into water systems, as can fertilizers that enrich the nitrogen
content of the soil. In terms of pool water, aside from the possible sources of nitrates already
mentioned, one of the main sources is human sweat and urine which contain nitrogen
compounds.
Being a nutrient for plants and algae, nitrates in the pool will tend to help algae and some
other organisms proliferate in the pool. Higher levels of algae and bacteria in a pool will
always require more chlorine as a disinfectant – increasing the demand for chlorine.
It is not the nitrate ion itself that creates the increased demand for chlorine, but rather the
increased amounts of microorganisms in the water that raises the chlorine demand.
Nitrites are not usually present in the environment in great numbers because as a chemical,
nitrite is less stable and prefers to be in the form of nitrate. Nitrites are often formed when
microorganisms ingest nitrate and release nitrite. In water distribution networks, nitrite can
also be formed by particular bacteria when water stagnates whilst also being rich in natural
nitrogen content.
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The presence of nitrogen compounds in your surface or groundwater usually indicates
contamination by ammonia and/or organismal proliferation. Examples of the kinds of things
that could lead to such a situation include non-organic over-fertilization and manure
seepage, careless wastewater disposal, and human sewerage entering water distribution
systems. It is sometimes possible that nitrites in groundwater can come from natural
vegetation. Surface water is much more likely to contain nitrates or nitrites than
groundwater, or closed water systems.
According to the W.H.O, the most important source of human exposure to nitrate and nitrite
is from our diet – through vegetables and meat. Vegetables are rich sources of nitrates and
meat is often preserved with nitrites, especially cured meats.
Nevertheless, it is possible that drinking water can become a major source of nitrate/nitrite
exposure and as such levels of both nitrate and nitrite are regulated for health and safety.
Some of the negative health effects of excessive nitrite/nitrate exposure (especially in infants
under six months of age) include shortness of breath and blue baby syndrome amongst other
complications.4
Controlling nitrates and nitrites in pools is a matter of simply maintaining proper
management of the pool environment and disinfection residuals – regular testing is vital to
catching nitrate and nitrite compounds early before microorganisms like algae use the
nitrogen as food and multiply.
The drinking water maximum guidelines for both nitrates and nitrites are listed in the tables
on the following two pages:
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Nitrate (R-NO3) Levels
POOL/SPA LEVELS1
Nitrate (NO3-) is not a relevant
issue for the operation of
pools/spas other than incidental
levels that may arise from water
sources used in the filling
process or contamination
sources from rain, spillage etc.
High nitrogen compound levels
in your pool help to feed algae
and bacteria. The increased
numbers of these organisms
create a greater demand for
chlorine.
Regular testing and proper
consistent pool/spa care should
prevent any problems.
DRINKING WATER LEVELS2 3
World Health Organization:
MAX:
50 mg/l (measured as Nitrate ions)
EPA:
MAX: 10 mg/l (measured as Nitrogen)
OPTIMAL:
≤ 50 mg/l (as nitrate ions)
(Less is always better)
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Nitrite (R-NO2) Levels
POOL/SPA LEVELS1
Nitrite (NO2-) is not a relevant
issue for the operation of
pools/spas other than incidental
levels that may arise from water
sources used in the filling
process or contamination
sources from rain, spillage etc.
High nitrogen compound levels
in your pool help to feed algae
and bacteria. The increased
numbers of these organisms
create a greater demand for
chlorine.
Regular testing and proper
consistent pool/spa care should
prevent any problems.
DRINKING WATER LEVELS2 3
World Health Organization:
MAX:
3 mg/l (as NO2-)
Most Common:
0.5 mg/l (as NO2-) = 50 mg/l (as NO3-)
EPA:
MAX: 1 mg/l (measured as Nitrogen)
OPTIMAL:
<< 1 mg/l (as Nitrogen)
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Closing Remarks
On the next and final page is our list of document resources and we would like to once again
encourage everyone who has come this far to definitely dive into some or all of them. They
contain a wealth of interesting and important information on water management, water
safety, health, water chemistry and much more.
Please remember to use your common sense and ask a professional should something be
unclear. It is vitally important that no mistakes are made with your drinking or bathing
water as any errors could lead to serious health problems and severe injury.
Many of the chemicals involved in water disinfection are extremely volatile and reactive –
the proper care and handling of such chemicals is beyond the scope of this work as are the
final choices you make in order to assess your personal pool or drinking water supply.
“We hope this document may have been of some small benefit”
-
The Authors
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Information & Data Sources Cited
1
World Health Organization. Water, Sanitation and Health Team. (2006). Guidelines for safe
recreational water environments. Volume 2, Swimming pools and similar environments.
Geneva: World Health Organization. http://www.who.int/iris/handle/10665/43336 (Accessed
06/2018)
2
World Health Organization. (2018). Global overview of national regulations and standards
for drinking-water quality. Geneva: World Health Organization; 2018. Licence: CC BY-NCSA 3.0 IGO. Available at:
http://www.who.int/water_sanitation_health/publications/national-regulations-andstandards-for-drinking-water-quality/en/ (Accessed 06/2018)
3
World Health Organization. (2017) Guidelines for drinking-water quality: fourth edition
incorporating the first addendum. Geneva: World Health Organization; 2017. Licence: CC
BY-NC-SA 3.0 IGO. http://www.who.int/water_sanitation_health/publications/drinkingwater-quality-guidelines-4-including-1st-addendum/en/ (Accessed 06/2018)
4
EPA (2009) EPA 816-F-09-004 National Primary Drinking Water Regulations. Available at:
https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-waterregulations#main-content (Accessed 06/2018)
5
E.P.A. (2017) National Secondary Drinking Water Regulations (NSDWRs) (March 8 update)
https://www.epa.gov/dwstandardsregulations/secondary-drinking-water-standards-guidancenuisance-chemicals#table (Accessed 06/2018)
6
ANSI/APSP-11 (2009) American National Standard for Water Quality in Public Pools and
Spas. The Association of Pool and Spa Professionals.
https://standards.nsf.org/apps/group_public/download.php/17496/ANSI-APSP-11%202009for-apsp-store.pdf (Accessed 06/2018). Latest version (2017) not available for free in the
public domain.