pH (power of hydrogen): pH is a measure of hydrogen ion (H+) concentration in water. It indicates relative acidity or basicity of pool water. It ranges from 0 (strong acid) to 14 (strong base) with 7 being neutral pH.

• Acceptable Range: : 7.2 - 7.8
• Desirable Range: : 7.4 - 7.6
  
  
• Low pH (below 7)
  • Water is acidic
  • Chlorine dissipates rapidly
  • Irritating to the eyes
  • Metals corrode and dissolve. May lead to possible staining
  • Water is clear (not in a good way)
    
    
• High pH (above 8)
  • Chlorine activity is slowed and inefficient
  • Scale formation and discoloration of pool walls
  • Water becomes cloudy
  • Filter is overworked
    

Total Alkalinity (TA): Total alkalinity is closly associated with pH but is it a measure of the ability of a solution to neutralize hydrogen ions. Since pH is measured from acid to base, total alkalinity's acid neutralizing (buffering) capacity in water helps prevent large variations in pH from small additions of acid or alkali components. Total alkalinity is a measure of water's resistance to change in pH.

• Acceptable Range: : 80 - 150 ppm
  
  
• Low total alkalinity (below 80 ppm)
  • pH will change rapidly when chemicals or impurities are added to the water
  • If pH drops rapidly, surfaces may corrode or etch in the pool/spa
    
    
• High total alkalinity (above 150 ppm)
  • pH becomes difficult to adjust
  • High pH often will cause other problems such as cloudy water, decreased sanitizer effectiveness, scale formation and/or filter problems.

Calcium Hardness: Calcium hardness is a measure of dissolved calcium in water. Calcium hardness is necessary to help prevent equipment corrosion, etching of plaster and wrinkling of liners.

• Acceptable Range: : 175 - 250 ppm
  
  
• Low calcium hardness (below 175 ppm)
  • Water is "soft"
  • Water may try to balance itself and "take" necessary calcium from equipment and pool wall
    
    
• High calcium hardness (above 250 ppm)
  • Water is "hard"
  • May contribute to scale formation and cloudy water

Cyanuric Acid *chlorine only*: Chlorine dissipates quick in the presence of UV (sunlight) when unstabilized. Proper stabilization (addition of cyanuric acid) results in a slower rate of chlorine dissipation due to sunlight.

• Acceptable Range: : 30 - 50 ppm
  
  
• Low cyanuric acid (below 30 ppm)
  • Chlorine is highly unstable in the presence of UV ray and will dissipate quickly
    
    
• High cyanuric acid (above 100 ppm)
  • May cause chlorine lock where ch and clouding of the pool water
  • Cyanuric acid is only lowered by draining and diluting the water with new fill water.
  • Stabilized chlorines should be limited when used for superchlorination as they will increase cyanuric acid levels.

CHLORINE

Types of Sanitation:

• Liquid Chlorine (Sodium Hypochlorite)
• Calcium Hypochlorite
• Dichloroisocyanuric Acid
• Trichloroisocyanuric Acid
• Lithium Hypochlorite
• Salt Chlorination

Free Chlorine: The amount of chlorine in the pool which has not reacted with substances/organics in the water. Is is the chlorine that is freely available to disinfect the pool water and oxidize with organics.

Combined Chlorine: The chlorine which has reacted with organics and is no longer freely available to disinfect the water. Chlorine that has combined with ammonia compounds produce chloramines which cause eye irritation and chlorine odor.

Total Chlorine: Concentration of free chlorine and combined chlorine. Optimal is when free chlorine is equal to total chlorine (all chlorine is free and available to disinfect)

Breakpoint Chlorination: Breakpoint chlorination is the process by which combined chlorine and some organics are "burned out" of the pool by the addition of large amounts of chlorine (shocking). When enough chlorine is added to the water the total chlorine residual will rise to a point that force the reaction of chlorine with ammonia. At this point nitrogen and chlorine are released from the water and the residual chlorine decreases. The point at which the chlorine residual suddenly drops is the breakpoint. It is when enough chlorine is added to pass the breakpoint that the combined chlorine compounds disappear and all remaining chlorine is now in a free state.

Acceptable Range: 1 ppm - 3 ppm

BROMINE

Types of Sanitation:

• Bromine Tablets
• Bromine Concentrate

Bromine is very similar to chlorine for pool water sanitation. The main form of bromine is bromo-chloro-dimethylhydantoin. It is part chlorine and part bromine. It is a very effective form of sanitation mainly used in heated pool or hot tubs.

Pros: Bromine is generally more stable than chlorine and is less subject to dissipation from UV rays. When bromine combines with organics (ammonia) the resulting bromamines are effective bactericides and do not produce the degree of odor or irritations that combined chlorines do. Bromine is also less affect by higher temperatures and is more active over a large pH range.

Cons: The cost of bromine per pound is significantly higher than that of chlorine.

Acceptable Range: 2 ppm - 4 ppm

SOFTSWIM (BIGUANIDE)

Types of Sanitation:

• Non-chlorine / Non-bromine system

Biguanides were originally developed as a pre-surgery anti-microbial scrub. The main form of biguanides used in pools and spas is polyhexamethylene biguanide (PHMB).

Pros: Easier to use with less chemical testing and less chemical addition than chlorine. It doesn't degrade with sunlight, temperature or fluctuations in pH like chlorine. Water feels smoother and biguanide stays fairly stable compared to chlorine (will dilute with fill water or rain water)

Cons: It is more costly than chlorine for sanitation purposes. It also tends to gum up filters and deposits "tub ring" at the water level. Biguanide in and of itself is not an oxidizer and must be used in conjunction with hydrogen peroxide to prevent organic waste accumulation. Biguanides can cause respiratory irritation at excessive concentrations.

Acceptable Range: 30 ppm - 50 ppm

SUPPLEMENTAL SANITATION SYSTEMS

Types of Sanitation:

• Copper / Silver Ion Generators
• Ozone Generators
• Ultra-violet Generators

There are a variety of supplemental sanitation methods on the market today. However, most states will not allow public or commercial pools/spas to use these as the primary sanitation method. Though they do provide some sanitation it may be slow acting or it may not produce enough residual. They MUST be used in conjunction with chlorine or bromine.

CHLORINE OR BROMINE OXIDATION:

• Superchlorination: In order to prevent buildup of chloramines it is necessary to periodically add large amount of new chlorine in order to hit breakpoint. Swimming pools should be superchlorinated once a week for optimal results. If combined chlorine is known than the amount of new chlorine added needs to be on the scale of ten times higher.
  
  
• Non-chlorine Shock: Oxidize organic compounds without the use of chlorine. No downtime during shocking (unlike chlorine-based shocks), however more expensive than chlorine shocks.
  

BIGUANIDE OXIDATION:

• Oxidation: Chlorine and bromine are effective oxidizing agents that can destroy organic contamination. Biguanide cannot destroy organic contamination and, therefore, hydrogen peroxide must be used in high enough concentrations to oxide the pool/spa for you.

ALGAECIDES:

• Prevention: Most algaecides are preventative measures that act as a surfactant/wetting agent and prevent algae from gaining hold of the pool surfaces. Usually most preventatives should be around 40% to 60% active ingredient for optimal prevention.

• Killers: Most algae killers are copper-based algaecides that are fast-acting, highly effective ways of destroying many types of algae. Usually effective within 24 hours of application, algae killers are ways to "nuke" the pool of unsightly algae blooms.
  
  
• Suppression: Most people opt to using borates for algae suppression than just algae preventative measures. On top of borates to inhibit algae growth, borates will lessen chemical demand in the water while making the water feel silky smooth. Addition of borates to a pool/spa only need to be topped off when water is splashed out or enough water is added to dilute the borate concentration.