How To Maintain Your Pool's Water Chemistry

When it comes to achieving a balance of swimming pool chemicals for chlorinated water, 5 primary keys exist. These five aspects are the keys to making sure the water chemistry in your chlorine swimming pool is correctly balanced, and these five aspects need checking every week to help prevent the formation of algae and bacteria in your pool. Your pool can become unhealthy and dangerous for swimming if bacteria and algae build up and cause green water and bug and mosquito infestation. Here are some of the things you need to inspect to make sure your swimming pool is clean and safe for swimmers.

#1 Level of Water Hardness: The level of water hardness constitutes the first key to maintaining a proper balance of chemicals in your swimming pool, and it contains two different parts: Direct Hardness Level and Indirect Hardness Level.

Direct Hardness Reading: This term refers to the fact that water hardness is directly caused by the water supply. If water is too hard, it is trickier to achieve the proper balance of swimming pool chemicals. Hard water is a result of partial minerals such as calcium and magnesium and plain old dirt. These things can be in your water straight from its source. Well water possesses a different degree of hardness compared to municipal water supplies. Not all cities have the same water hardness in the municipal supply. The originating source of the water is the key factor.

The indirect hardness level is the level of hardness that results from exposure to the chemical compounds used to treat the pool water. The hardness level of the water chemistry of your pool will increase as you continue to add chemicals to the mix.

If your water becomes too hard, the chemicals you are using won't be able to work effectively. Mineral deposits can then build up on the surfaces of your pool and pool equipment. Additionally, the water, itself will contain excessive minerals. Insufficient water hardness, which is rare, makes the water corrosive enough to erode the pool finish. The solution to increasing your pool water's hardness lies in using something called calcium chloride.

Water hardness in the range of two to four hundred parts per million (PPM) is considered optimal and harmless. You may have to drain some or all of your pool water and refill if your water gets too hard.

#2 Chlorine concentration: The concentration of chlorine in pool water is number two on the list for achieving balanced swimming pool chemicals. Chlorine is more important than any other substance when referring to the sanitation of a chlorine pool and the destruction of harmful algae and bacteria. There needs to be just the right amount of this chemical, however, as using too much will make it uncomfortable to swim in the pool, while using too little promotes the growth of algae and bacteria.

Pool chlorine can be divided into two types. These basic classifications are “useable” and “used” chlorine levels. The total chlorine level in pool water consists of both useable and used chlorine.

Free or Usable Chlorine is the chlorine that is hard at work killing bacteria and algae and sanitizing your pool. The most critical type of chlorine that must be maintained is the usable chlorine (also called free chlorine), as this is the stuff that actually kills off bacteria. The lowest permissible amount of useable chlorine in a pool is one part per million. Using a lower amount than this makes it impossible for the chlorine to neutralize harmful bacteria. Ten parts per million is the greatest amount of useable chlorine that is permissible. If this number is higher, the water will irritate swimmers and even pose a danger. Optimally, your pool's level of free, useable chlorine should range from one to three parts per million.

Used Chlorine refers to the chemical that has finished 'working' in your pool, thus it is no longer effective. This type of chlorine just floats around in your pool, which makes the water harder and less comfortable to swim in. When checking chlorine levels in your pool, it's important to understand that total chlorine and usable chlorine are two different things. A goodly proportion of total chlorine may be chlorine that is already used up and useless.

If there is a lot of useless chlorine in a pool, the pool must be “shocked“. When you give your pool a super-sized dose of usable chlorine, the process is known as shock. Shocking a pool burns off and kills off the old, expended chlorine. This treatment eases water hardness so that the usable chlorine can function efficiently to keep your pool safe and clean.

#3 Proper pH: Having the right pH level is the third secret to achieving a balance of swimming pool chemicals. The pH number indicates the alkalinity or acidity of the water filling the pool. It's best to keep your swimming pool levels fairly basic. Testing kits for pH are numbered to demonstrate the degree of acidity or baseness of the water. A pH reading below 7.0 is more acid, while a reading above that is considered base. A level that falls in the range of 7.2 to 7.8 is optimal for swimmers.

Insufficient pH: When water exhibits acidity or low pH, it is corrosive enough to potentially damage the pool's finish or equipment. This burns away the chlorine and it can no longer do its job. Low pH levels can cause irritation to skin and eyes. To raise the pH number, apply some sodium bicarbonate or soda ash to the pool's water.

Water is too basic: If the water's PH is over a certain amount, it will cause swimmers to become uncomfortable, and it will reduce the clarity of the water. Water that is too basic can also cause deposits of calcium and other metals to accumulate, which can cause parts of your pool to become discolored or damaged. If the pool water's PH is too high, use muriatic acid to increase its acidity.

#4 Conditioner level is the fourth element you must consider in swimming pool balance. The chemical used to promote chlorine level stability is called cyanuric acid, which is also referred to as a pool conditioner. The sun's ultraviolet rays dissolve chlorine and cause it to dissipate rapidly. Cyanuric acid works to safeguard chlorine against the sun. It is important to apply cyanuric acid prior to adding chlorine when filling up your pool to allow the chlorine to work properly. As the water evaporates or the pool is cleaned out as part of regular maintenance, the supply of cyanuric acid needs to be maintained. The perfect amount of cyanuric acid in a swimming pool is somewhere between 30 to 80 PPM; this ensures that the sun does not damage the chlorine in the pool. Cyanuric acid readings in excess of 100 PPM are elevated and require reduction. To remedy a case like this, it is necessary to drain out some of the pool's water and replace this with clean water.

#5 Total Alkalinity or TA is the fifth thing you must keep in mind when considering pool balance. TA represents the total amount of alkalinity in the water that fills the pool. The total alkalinity of your pool's water should always be between 80 and 120 parts per million. You can prevent sudden changes in pH and keep your pH level stabilized by adhering to this TA range. Here is what can happen with excessively low TA levels: 1/ Excessive algae growth, 2/ Erratic pH levels, 3/ Staining and etching of pool surfaces, 4/ Corrosion of metal components. Cloudy water is a result of low TA. In this circumstance, it will be difficult to maintain a balanced pH level, and your chlorine treatments will be ineffective. Additionally, you will need to make constant acid adjustments.

When TA concentration requires elevating, the solution is application of soda ash or sodium bicarbonate. This is the one chemical capable of elevating TA concentration without dramatically altering pH balance. You should apply muriatic acid in order to reduce a TA level that is too high.

So, at the end of the day, the main things to remember when balancing your pool chemicals are that you must check them frequently and you must make proper adjustments when necessary. When the five important points presented here are followed by either your pool company or yourself, you can rest assured, you will have a safe, inviting pool to enjoy as you wish.


Tip: Contact a pool cleaning service if you need help maintaining your pool chemicals on a regular basis.

Pool Cleaning Professional

Pool Care Articles

Learn more about how you can
keep your swimming pool in
top shape...

Click here to read our articles
about swimming pool
maintenance and care.