• The variety and types of chemicals available for pools can quickly become overwhelming. Which are necessary? What choices are best? Saltwater systems, while expensive, are a chemical-free choice. For traditional pool chemical choices, analyze your water either at home with a kit, or by taking a sample to a pool supply professional. Then choose among the basics.
  
  

Chlorine/Bromine

• "The two most important things to remember about the health of your pool are that it must be sanitized and it must be balanced," states Pool Gear Plus online. Together with a filter and pump, water sanitizer protects the health of swimmers. Chlorine and bromine are the most common options.
  
  Chlorine tablets are the best choice for the average pool. Placed in a floating feeder, they slowly release sanitizer until dissolved. Bromine is another option often chosen by those with sensitive skin. However, it is more expensive than chlorine.
  
  

Shock

• Regardless of the brand of shock chosen, it is helpful to proper pool maintenance. Because chlorine grows weaker over time, shock is added to neutralize trace chlorine and contaminants. New chlorine can then be added. Shock is often relied upon as a general cure for many water contamination issues.
  
  

PH Agents

• Your swimming pool is "balanced," Hines Pool and Spa explains, when "it is not corrosive (low pH or acidic) or aggressive (high pH or alkaline)." The pH, total alkalinity and water hardness (caused by calcium) must be balanced as well.
  
  Comparing strips from a pH test kit dipped in pool water to the chart in the kit determines the pH. An ideal pH is between 7.2 and 7.8.
  
  To lower the pH of alkaline water, use pH decreaser (muriatic acid or dry acid). Another alternative is carbon dioxide, but its addition is more complicated and involved. Alternately, pH can be raised in acidic water by adding pH increaser (soda ash or sodium carbonate).
  
  Total alkalinity, Pool Gear Plus explains, "refers to how much alkaline is in the water" and is related to pH because, "High alkaline water leads to high pH. Low alkaline water leads to low pH." Meaning, if the total alkalinity is very high, it prevents the pH from remaining stable and you must constantly adjust the pH. The best chemical option is sodium bicarbonate--baking soda--bought at a pool supply store.
  
  

Calcium Increaser

• Finally, to keep your pool water balanced, use a calcium increaser such as calcium chloride. It keeps the water from being too soft. Soft water is aggressive--meaning corrosive--and can damage plaster and equipment. It can also cause water to change colors, so add a calcium increaser as needed.
  
  

Other Chemicals

• Other chemicals, while not essential, may be required in certain situations. Algaecide will treat the green tint caused by algae brought in by animals, sun and rain. Stabilizers like cyanuric acid will help maintain chlorine levels, and you will need to use less sanitizer as a result. Clarifiers clear extremely cloudy water that may be caused by poor filtration, dust, pollen, residues from chemicals or dead algae suspended in the water. Metal removers and other water conditioning chemicals are available as well. However, unless problems are experienced and water has been tested and proven to need more, most of these chemicals are unnecessary and costly.