Code of Maine Rules › 10 - DEPARTMENT OF HEALTH AND HUMAN SERVICES › 144 - DEPARTMENT OF HEALTH AND HUMAN SERVICES - GENERAL › Chapter 202 - RULES RELATING TO PUBLIC SWIMMING POOLS AND SPAS › Appendix 144-202-A - CHEMICAL OPERATIONAL PARAMETERS

Current through 2024-29, July 17, 2024
These standards set forth the operational parameters required
				  for the proper chemical treatment and maintenance of public pool and spa
				  waters.
Chemical treatment alone will not produce sanitary pool and
				  spa water. A filtration system in proper operational condition is also required
				  to attain clear, and sanitary water.
Public Pools - NSPI-1, NSPI-4, NSPI-9
Public Spas - NSPI-2
1. Sanitizer Levels
a. Free chlorine, ppm
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-4 NSPI-9
1.0
1.0-3.0
4.0
Hot water/heavy use may require operation at or near
						  maximum levels. 
						  
													 Test kits are available for a variety of free
								chlorine ranges.
													 Free chlorine test color (DPD) may be
								completely or partially bleached by chlorine levels greater than 5 ppm to give
								a false low reading. 
												For appropriate test kit, consult pool
						  professional or test kit manufacturer.
Regular oxidation is
						  recommended and remedial practices may be necessary.
NSPI-2
3.0
4.0-5.0
8.0
Public Spas: 
						  
													During hours of operation, test the water
								hourly, record results, maintain the ideal range continually and shock treat at
								the end of the daily use period.
b. Combined Chlorine, ppm
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-4 NSPI-9
0
0
0.2
High combined chlorine results in reduced
						  sanitizer efficacy. Take remedial action to reduce combined chlorine. Other
						  signs of combined chlorine: Sharp chlorine-like chlorinous odor and eye
						  irritation (e.g., mucous membrane).
NSPI-2
0
0
0.5
c. Total Bromine, ppm
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-4 NSPI-9 NSPI-2
3.0 6.0
3.0-5.0 6.0-8.0
7.0 10.0
Hot water/heavy use may require operation at or near
						  maximum levels. Regular oxidation is recommended. During hours of operation,
						  test the water reqularly, record results, and maintain the ideal range
						  continually. NSPI-2: Test water before use. During extended use test water
						  hourly. Shock treat after use.
2. Chemical Values
a. pH
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
7.2
7.4-7.6
7.8
Operating pH at the minimum level requires alkalinity and
						  hardness to be operated at a higher level. At maximum pH, calcium hardness and
						  total alkalinity may have to be adjusted downward to maintain proper water
						  balance. (See "saturation index" in NSPI Glossary.)
If pH is too
						  high: 
						  
													 Low chlorine efficacy
													 Scale formation
													 Cloudy water
													 Eye discomfort 
												 If pH is too low: 
						  
													Rapid dissipation of sanitizer
													 Plaster and concrete etching
													Eye discomfort
													 Corrosion of metals
													Vinyl liner wrinkling
b. Total Alkalinity (Buffering) ppm as
						  CaCO3
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
60
80-100 For calcium hypochlorite, lithium hypochlorite
						  and sodium hypochlorite 100-120 For sodium dichlor, trichlor, chlorine gas and
						  bromine compounds
180
If total alkalinity is too low: 
						  
													 pH bounce 
													Corrosive tendency . 
												 If total alkalinity is too high: 
						  
													 Cloudy water
													Increased scaling potential
													pH tends to be too high
												These values are based on carbonate
						  alkalinity
c. Total Dissolved Solids (TDS)
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
NA
NA
1500 ppm greater than TDS at pool start-up* *Start-up
						  TDS includes source water TDS and any other inorganic salt added at start-up.
An increase in TDS may indicate an accumulation of
						  impurtities during the course of operation. Excessively high
TDS
						  may lead to hazy water and scale formation, corrosion of fixtures, and may
						  inhibit sanitation. TDS can be reduced by partial draining and addition of
						  fresh water.
For spas: TDS should be periodically reduced by
						  draining. (See Section K. Water Replacement Procedure)
d. Calcium hardness, ppm as
						  CaCO3
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-4 NSPI-9
150
200-400
1000
Lower alkalinity and lower pH must be used
						  with hardness over 500 ppm.
NSPI-2
100
150-205
800
e. Heavy Metals
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
NA
NA
If excessive heavy metals (such as copper, iron, and
						  manganese) are present: 
						  
													 Staining may occur
													 Water may discolor
													 Filter cycle may decrease and require more
								frequent backwashing
													 May indicate pH to low, corrosion, etc.
3. Biological Values
(Maintaining adequate sanitizer levels is critical to prevent growth of
						  algae and bacteria)
a. Visible Algae
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
None Visible
None Visible
None Visible
If algae growth is observed recommendations may include
						  but are not limited to: 
						  
													Superchlorinate the pool or spa.
													 Use an EPA-registered algicide according to
								label directions.
													 Supplement with brushing and vacuuming.
								
												Some algicides may cause foaming.
b. Bacteria
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
None
None
None
If bacteria count exceeds 0 CFU/100 ml, superchlorinate
						  and follow proper maintenance procedures.
4. Stabilizer (when used)
a. Cyanuric Acid, ppm
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
10
30-50
150
If stabilizer is too low: Chlorine residual is rapidly
						  destroyed by sunlight.
If stabilizer is too high: May reduce
						  chlorine efficacy to algae.
NOTE: Stabilized chlorine use is
						  prohibited for indoor pools. Cyanuric acid does not stabilize bromine
						  sanitizers.
5. Oxidation (Regular oxidation is
						  recommended for pools and spas with normal bather load as a preventative
						  treatment)
a. Chlorine Products
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-4 NSPI-9
As needed
Weekly
Determined by bather load, weather
						  conditions, etc.
Some high use pools may require oxidation
						  several times per week.
Regular oxidation is recommended to prevent
						  the build-up of contaminants, maximize sanitizer efficiency, minimize combined
						  chlorine and improve water clarity.
NSPI-2
At the end of each day facility is used.
b. Potassium Monopersulfate
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-4 NSPI-9
As needed
Weekly
Determined by bather load, weather
						  conditions, etc.
Some high-use pools may require oxidation
						  several times per week.
Regular oxidation is recommended to prevent
						  the build-up of contaminants, maximize sanitizer efficiency, minimize combined
						  chlorine and improve water clarity.
Potassium monopersulfate will
						  measure as combined available chlorine in DPD test system.
Refer to
						  test kit manufacturer's directions.
NSPI-2
At the end of each day facility is used.
c. Hydrogen Peroxide
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
Monthly
As needed
Determined by bather load, weather conditions, etc.
Hydrogen peroxide should not be used as an oxidizer for
						  pools and spas sanitized by chlorine dioxide.
d. Chlorine Dioxide
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-4
As needed
3-4 weeks
Determined by occurrence of biofilms in skimmer or
						  plumbing or by abrupt disappearance of hydrogen peroxide.
No comments
6. Remedial Practices
a. Superchlorination
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
Follow label directions. Use a registered chlorine
						  sanitizer.
Do not enter pool or spa until water meets the
						  prescribed values in Section A. Some sysptoms that may indicate a need for
						  superchlorination are: 
						  
													Cloudy water
													 Slime formation
													 Musty odors
													 Difficulty in maintaining a sanitizer residual
								
													 Algaae and/or high bacteria counts
b. Superchlorination to establish
						  breakpoint, dosage in ppm
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
At least 10 times combined chlorine
High dosage may be required to satisfy chlorine demand.
						  If combined chlorine persists, water replacement should be considered.
c. Shock Treatment
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
Some conditions that may indicate a need for shock
						  treatment are: 
						  
													 Cloudy water
													Difficulty in maintaining a sanitizer residual
								
													 Periods of heavy bather use 
													 Adverse weather 
												Non-chlorine shocks are not sanitizers. They
						  are effective in oxidizing organic contaminants. If the purpose of shock
						  treatment is to treat bacteria or visible algae, an EPA registered product for
						  that use should be used; follow label directions.
Spas should be
						  shock treated on a daily basis when used.
d. Chlorine Dioxide
NSPI Standard
Minimum
Ideal
Maximum
Comments
As needed
Determined by occurrence of biofilms in skimmer or
						  plumbing or by abrupt disappearance of hydrogen peroxide.
Follow label directions.
e. Clarification/Flocculation
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
As needed
Follow manufacturer's directions.
f. Algicides
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
As needed
Use U.S. EPA-registered products. Follow manufacturer's
						  directions.
Use of some algicides may cause foaming.
g. Foam Control
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
As needed
Foam may harbor persistent microorganisms.
If foaming is not adequately controlled, consider daily shock treatment, water
						  replacement, or an appropriate anti-foam agent. Follow manufacturer's
						  directions.
7. Temperature
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
Personal preference Personal preference
For pools: 78°F-82°F For spas: Personal
						  preference
Personal preference 104°F
If temperature is too low: 
						  
													 Bather discomfort
												 If temperature is too high: 
						  
													 Excessive fuel requirement
													 Increased evaporation
													 Bather discomfort
													 Increased scaling potential
													 Increased use of sanitizers 
												Overexposure to hot water may cause nausea,
						  dizziness and fainting.
8. Water Clarity
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
The deepest part of the pool or spa and/or main drain
						  must be visible and sharply defined.
If water is turbid: 
						  
													 Sanitizer level may be low 
													 Filtration/circulation system may require
								maintenance
													 Improper chemical balance (Appendix
								A(2))
													 Consult remedial practices (Appendix A(6))
9. Ozone
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-4 NSPI-9
Concentration in
						  air above pool or spa water, ppm
0.1 over 8-hour time weighted average.
Serves as oxidizer of water contaminants. Must
								be used with EPA-registered sanitizer.
													Indoor installations should have adequate
								ventilation.
10. Oxidation Reduction Potential
						  (ORP)
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-1 NSPI-2 NSPI-9
650 MV
When chlorine or bromine is used as the primary
						  sanitizer, ORP is commonly used to control sanitizer feed. The use of ORP
						  controllers does not eliminate or supercede the neeed for testing the sanitizer
						  level with standard test kits.
ORP reading may be affected by a
						  number of factors including, but not limited to pH, probe condition, cyanuric
						  acid, sanitizer type, and supplemental oxidizers.
Follow
						  manufacturer's recommendations.
11. Water Replacement
NSPI Standard
Minimum
Ideal
Maximum
Comments
NSPI-2
Water in spas/hot tubs that have high bather use
						  requires partial or complete replacement of water periodically.
Water in spas/hot tubs that have high bather use
						  requires complete replacement of water per the replacement guidelines below.
Water replacement is necessary to dilute dissolved
						  solids, to maintain water clarity, and to do necessary routine maintenance.