Balancing Swimming Pool Chemicals: Keeping Your Chlorine Pool's Water Chemistry in Balance

by Pool Builders on 11-20-2011 in Articles

There are 5 major aspects to balancing swimming pool chemicals in a chlorine pool. These 5 aspects are key to keeping your chlorine swimming pool water chemistry in balance, and should be checked on a weekly basis to help reduce the chance of unwanted algae and bacteria from growing. Algae and bacteria will cause a pool to turn green, attract mosquitoes and other bugs and make a pool less healthy or even dangerous to swim in. Here is a breakdown of the important things to look at to ensure a clean safe pool to swim in.

1) Water Hardness Level

Water hardness level is the first key to balancing swimming pool chemicals, and consists of two components: Direct Hardness Level and Indirect Hardness Level.

Direct Hardness Level - Hardness in your water is direct result of the source your water comes from. When the water hardness is too high, it makes balancing swimming pool chemicals difficult. The biggest things that make water hard are dirt and partials (Magnesium and calcium from the dirt and atmosphere to be exact) that are in your water when it arrives at your house from wherever it came from. If you get your water from a well it will have a different hardness level than if you get it from the city you live in. Some communities have harder water than others. It all depends on the source.

Indirect Hardness Level - Hardness in a pool is indirectly affected by the various chemical compounds that dissolve in your pool's water. As you add chemicals to your pool and they do their job, they get used up and start to add to the harness level of your pool's water chemistry.

When water gets too hard it has no room to let the chemicals that balance a pool to dissolve and work, and it has a tendency to start creating deposits or minerals on your pool's floor and walls and pool equipment due to the high concentration of the minerals in the water. When water hardness is to low (this is not the case too often) water is corrosive and will start eating away at your surfaces. In this case you can add a chemical called Calcium Chloride to bring the harness level up.

Perfect water hardness levels should be between 200-400 ppm of minerals to be safe and effective. If water in your pool becomes too hard the only way to resolve it is to drain your pool partially or completely, and refill it with new fresh water.

2) Chlorine Level

The chlorine level in the pool is the second key to balancing swimming pool chemicals. When talking about sanitizing a chlorine pool and killing unwanted algae and bacteria, chlorine is the most important chemical to have. It is important to keep this chemical in balance though, because if you have too much it can irritate swimmers' skin and eyes and be unhealthy, and if you have too little then algae and bacteria can grow.

There are two forms chlorine takes when it is in your pool. I call the two forms "Useable Chlorine" and "Used Chlorine". Combined (Useable and Used) make up the "Total Chlorine" in your pool.

1) Useable Chlorine (AKA Free Chlorine) is the chlorine that is actively working, sanitizing and killing unwanted algae and bacteria in your pool. This useable, or free chlorine level, is the most important chemical to keep in balance. The minimum useable chlorine there should be in your pool is 1 ppm. Less than this and there will not be enough to sanitize and kill. The most useable chlorine there should be in your pool is 10 ppm. More than this, and it becomes irritating and unsafe to swim in. The ideal range for perfect pool chemistry is to have 1-3 ppm of free, useable chlorine in your pool.

2) Used Chlorine is the chlorine in your pool that has already done its job and is now ineffective. It is the part of the chlorine that is just floating around adding to the hardness of your water and it is not killing anything. Sometimes when people check chlorine levels in pools, they see that there is a good amount of "Total Chlorine", but that does not ensure that there is enough useable chlorine killing things because the used chlorine is done and used up.

This is where "Shocking" a pool comes into play. Shock is an extra large dose of useable or free chlorine and when a pool is shocked the useable chlorine sanitized, kills and burns off the used chlorine. This helps give room in the hardness level of the pool for the useable chlorine to move around and do its job in keeping your pool clean and safe.

3) PH Balance

PH balance is the third key to balancing swimming pool chemicals. PH is the index to show how acidic or alkaline (basic) pool water is. The ideal for a swimming pool is just being on the basic side. Any PH tester has numbers that will show you how acidic or basic your water is. Water that reads lower than 7 is acidic, and water that reads higher than 7 is basic. The perfect range for swimming is between 7.2 and 7.8.

Low PH - If a pool is too acidic or has a low PH then the water can corrode fixtures or equipment or the surface of your pool. This also causes chlorine to be killed off and stops its effectiveness. If the PH is too low swimmers' skin and eyes can become irritated as well. If the PH level is too low, Sodium Bicarbonate (Soda Ash) needs to be added to your pool.

High PH - If a pool is too basic or has a high PH, then the water can also be uncomfortable to swim in, and the water can become cloudy. A High PH can also cause calcium and metals to come out of your pool surface and create stains and deposits on pool equipment and walls. Muriatic Acid is the chemical that is added to a pool to lower the PH level if it becomes too basic.

4) Conditioner Level

Conditioner level is the fourth key to balancing swimming pool chemicals. Cyanuric Acid ("Stabilizer" or "Conditioner") is the chemical that is added to a pool to stabilize the chlorine balance. Chlorine is affected and dissolved fast by the ultraviolet rays of the sun. Cyanuric Acid protects chlorine from the sun. When a pool is filled, Cyanuric Acid needs to always be added first so that the chlorine can do its job. Also, as evaporation happens or a pool is partially drained and refilled, cyanuric acid also needs to be added. The ideal level of cyanuric acid in a pool should be between 30-80 ppm for great effectiveness so that the chlorine is not harmed by the sun. If the level of cynanuric acid ever reads higher than 100 ppm, then it should be lowered. In such a situation, the only way to lower it is to partially drain the pool and add fresh water.

5) Total Alkalinity (TA) Balance

Total Alkalinity is the fifth key to balancing swimming pool chemicals. The Total Alkalinity, or TA, is the measurement of how much alkaline substances are in your pool's water. When checking your pool TA level it should read between 80-120 ppm. When the TA is in this range, it helps stabilize your PH level and prevents rapid PH changes. If your TA level is to low, metals start to corrode, your pool walls and floor become etched and stained, the PH level bounces up and down and water can become green from algae growth. If your TA level is too high your water can become cloudy, the PH level will be hard to keep balanced, chlorine will not be as effective and your pool will constantly need more acid.

If you need to raise the level of your TA, add sodium bicarbonate (Soda Ash) to your pool. It is the only chemical that will raise the level of your TA without drastically changing the PH level. If you need to lower the TA level in your pool, add Muriatic acid.

In conclusion, the key to balancing swimming pool chemicals is checking their levels regularly and adjusting them as needed. If you or the company you hire to maintain your pool keeps an eye on these 5 things you will always have a clean, safe and enjoyable pool to swim in all year long.

Note: This article lists the basic chemicals needed for pool maintenance. Pool chemical safety should always be kept in mind when dealing with any of these chemicals. Please consult a professional and chemical manufacturer for instructions on all chemicals listed above for the amounts to be used and the process of introducing them to your pool. All of these chemicals are dangerous and can be very unsafe if used in the wrong way. The manufacturer's pool chemical material safety data should always be taken into account when dealing with these chemicals.

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