Clean swimming pool water
Credit: Allen-Douglas

Controlling the amount of chlorine in a swimming pool is important for maintaining clear water and avoiding algae and bacteria growth.  No one likes a cloudy pool or wants to deal with scrubbing and cleaning up after an algae attack.  Even with an automatic dispenser it is sometimes challenging to keep a high enough amount of chlorine in the pool to work effectively.   In order to keep pools clean it is generally recommended to have free-chlorine levels between 2 and 4 parts per million.  Chlorine levels should never be allowed to fall below 1 part per million.  This is assuming that the pH level of the water is in the normal 7.2 to 7.8 range.  For lower pH levels the normal level or chlorine will not be effective.  Both pH and chlorine are easily testing by using pool test strips or a simple chemical water test using a test kit.  Here are some tips to keeping a high enough chlorine content in a swimming pool to avoid water quality issues.

Method 1 For Increasing Chlorine in a Swimming Pool

Method 1 for increasing chlorine levels in a swimming pool to keep the water sparkling clean is generally the most expensive, depending on area energy costs.  In locations where electricity is expensive like California, this option may be more economical.  Method 1 is to use a weekly shock.  Shock is a packet of ground up material that has a high chlorine content.  The shock is generally pre-mixed with water then poured into the pool.  Each type of shock has its own instruction so be sure to read the manufacturer's recommendations and safety warnings.  Packets of weekly shock generally cost between $4 to $12.  Pool suppliers generally recommend this method since it increases their sales.  It is a great method to keep the chlorine levels high and to keep out the bacteria from the water.  It is also great for those who do not want to tinker with their pool settings and just want to enjoy clear water.  This method can be the most expensive alternative to keeping chlorine levels high.  Over a 4 month pool season, $8 per week would cost a pool owner approximately $128.  This is a manufactured specialty product that is quite expensive, but is also very effective. 

Keep in mind that pool owners should not simply dump the shock in once a week and swim in the pool.  Chemical testing of the water for pH, chlorine and other important substances must always be performed to keep water safe for both swimmers and the pool liner, concrete, or plaster. 

Automatic pool chlorine dispenser
Credit: Allen-Douglas

Method 2 for Increasing Chlorine in a Swimming Pool

The second method for increasing chlorine in a pool requires the use of a pool system with a system timer and an automatic chlorine dispenser.  In areas that have high electricity costs, this method may actually be less economical than method 1. 

  • High quality chlorine tablets should always be used in a pool, particularly if you are having problems maintaining a high enough chlorine count.  Cheap chlorine tablets sometimes contain low amounts of chlorine, but contain filler material.  
  • Most automatic chlorine dispensers have a release value that controls the amount of water allowed to filter through the dispenser.  Increase the setting on the valve and allow the system to run for a day.  Then check the pool chlorine level.  Continue to increase the valve setting until the swimming pool reaches the desired level of chlorine.
  • If the valve setting is turned all the way up and chlorine levels are still not reaching the desired level, the next step is to increase the amount of time the pool pump is running each day.  Change the settings on the pool system to allow it to run longer.  The longer the pool runs, the more chemical released into the water.  Increase the amount of time the pool runs, until reaching the desired result.  When the air temperature is higher and more sunlight enters the water, more chlorine is typically needed to reach the demand of maintaining enough free chlorine.  The amount of time the pool pump runs will likely need to vary based on the air temperature and direct sunlight exposure.
Floating swimming pool chlorine dispenser
Credit: Allen-Douglas

Method 3 for Increasing Chlorine in a Swimming Pool

The easiest and most economical way of increasing chlorine in a swimming pool use of a floating dispenser.  Floating dispensers are inexpensive and can be left in the pool anytime additional chlorine is desired.  These units typically accept 3" or smaller tablets.  After inserting the tablets, a sliding mechanism allows the varying amount of water in the chamber to mix with the chlorine tablets.  Power is not needed for these units.  They will add chlorine to the water even when the pump is not operating.  Remove the floating dispenser from the pool when people swim in the water since higher concentrates of chlorine are present in the water directly around the unit.  Check with the manufacture's recommendations and warning for the specific use of these products.

These are the best methods of increasing chlorine content in a swimming pool. One method or a combination of these methods are typically useful to find the perfect set up for every pool.  Remember what works best in cooler weather in May may not work the same during the hottest weeks of the year.