Why Do Pools Need to Be Treated?
There are three primary areas to consider in pool maintenance: cleaning, circulation and water filtration. In this article, we’ll focus on cleaning chemicals. For information on the other aspects of pool upkeep, read our article on general pool maintenance, How to Maintain a Pool.
Failing to properly treat your pool water is not only damaging to a swimmer’s health, but it can also prove costly to the pool and your pool’s plumbing. The four primary areas of treating pool water are:
- pH balance
- Disinfecting
- Algae control
- Calcium control
This guide explores chlorine and saltwater pools, each treatment area and their purpose. With a little planning, you’ll have a safe and clean pool for friends and family to enjoy.
Chlorine Pools
Chlorine pools need the addition of chlorine to ward off bacteria, cloudy water and prevent algae growth. Chlorine pools also need water balancing more often than a saltwater pool. You can assess the pH, chlorine and alkaline levels and water hardness with test strips. Testing weekly and adding the appropriate chemicals to retain an optimal balance will keep your pool water looking and feeling its best.
Saltwater Pools
Saltwater pools are gaining popularity as they’re chlorine-free, which helps reduce skin and eye irritation. With a saltwater pool, salt is added directly to the pool water. A device called a salt chlorinator sanitizes the water through electrolytic chlorine generation. The chlorine is created from the salt. This eliminates the need for adding the chlorine manually, but the sanitizing agent is still chlorine. This leaves the pool water feeling softer, silkier and gentler to skin, hair, eyes and clothing, without leaving behind a chlorine odor. Because saltwater pools don’t need harsh chemicals, they often have overall lower maintenance costs.
What Pool Chemicals Do I Need?
There are four main objectives that pool chemicals are used for: to balance, disinfect, shock and defend. The following explains the part that each chemical plays in helping to make your pool water sparkle.
Chlorine
Chlorine is added to swimming pools to sanitize the water. It also helps to get rid of algae and break down non-living substances like oils and organic waste. There are two familiar types of chlorine: liquid and trichlor. Liquid chlorine is a non-stabilized form that’s easy to apply and is used in both residential and commercial pools. Liquid chlorine is cheaper than other forms of chlorine but has a shorter effective period, and it requires more frequent application to maintain proper sanitation.
Trichlor is a form of chlorine that’s stabilized so it can withstand ultraviolet rays. It’s available in tablet form, making application easy. Chlorine tablets provide a slow release of high-quality sanitizer, but you’ll need to check various places in the pool to ensure even distribution. To ensure even distribution, use an in-line chlorinator or place the tablets in the skimmer basket. For more information about pools and chlorine, see our article How to Chlorinate a Pool.
Cross-contamination of different chlorine types can release toxic chlorine gas and trigger fires and explosions. They can also cause severe health problems, including chemical burns to the skin and eyes, severe breathing difficulties, chest pain and in some cases the chlorine gas can be fatal. Never mix or store different types of chlorine together. Don’t let one chlorine product touch containers or equipment used for another. Read, understand and follow all instructions for pool chemicals, including proper use, storage, safety precautions and protective equipment.
Water Balance
Balanced water improves swimmers’ comfort and skin by preventing dryness and irritation and protects your pool and equipment. Test strips and test kits can check for total chlorine, bromine, pH, total alkalinity, total hardness and cyanuric acid (CYA) levels. Set up a bi-weekly test schedule to keep your pool water fresh and clean.
Pool Shock
Using pool shock will prevent many common pool water problems. Shocking raises chlorine temporarily to destroy contaminants, kill and prevent occurrences of green, black and mustard pool algae that can discolor the water and reduces strong chlorine odors, which helps keep the water clear. It’s recommended to add shock weekly, as well as before and after pool parties, storms and exceedingly hot temperatures.
Shocking also eliminates bacteria buildup. A good rule of thumb is to add a pound of pool shock for every 10,000 gallons of pool water.
Algae Control
Algae can discolor both your pool water and pool surfaces, like walls and ladders. This growth is usually caused by a lack of sanitizer or by pH levels that are out of balance. If algae is present, it’s best to balance the pH level first and then add algaecide. Cleaning the pool surfaces, like walls and steps, and adding algaecide weekly will help curtail any new algae growth.
Water Clarifier
Hazy pool water is a common problem caused by low sanitizer, imbalanced water chemistry, thunderstorms or irregular water pump and filter upkeep. The cloudiness is due to extremely tiny dirt and debris particulate that are unable to be filtered out by the pool’s system. Pool water clarifiers help bind these smaller particles together into larger particles that are easier for the filter to collect and remove. Clarifiers usually take about 2 to 3 days to complete the cleaning action.
Flocculant is another type of water cleaner that also binds debris together. This product builds larger bonds that sink to the pool bottom and require vacuuming.
Scale, Metal and Stain Control
Using a scale, metal and stain formula for your pool will help protect against scale buildup and stains from calcium, magnesium, copper, iron and other minerals and metals. Use this formula when you open and close your pool, or for spot treatments during the season.
Pool Salt
You may not think of pool salt as a chemical but adding salt to a saltwater pool can make your water cleaner and softer to the skin when compared to traditional chlorine pools. There are three types of salt designed for pool use: solar, mined and mechanically evaporated. Each of these is a coarse grind and should be 99% pure sodium chloride. This purity helps keep your pool from staining or damaging your pool’s equipment.
A salt chlorine generator (or saltwater chlorinator) converts the salt grains into chlorine, which helps sanitize your pool water without the higher levels associated with liquid chlorine or chlorine tablets.
Never add Epsom salt, Himalayan salt or rock salt to pool water. They can cause corrosion and scaling on your equipment, disrupt the pool’s chemical balance and cause cloudiness and staining.
Pool Chemical Safety
Pool chemicals are designed to manage water problems, but they can be harmful to humans and animals when handled improperly. Chemicals can cause skin burns, eye damage and can be fatal if swallowed. Follow these pool chemical safety precautions:
- Keep all pool products away from children and animals.
- Wear rubber gloves and protective eyewear.
- Wash clothes and hands immediately after handling chemicals. If pool chemicals touch your skin, rinse with cold water for 15 minutes and seek medical help if you have a reaction.
- Follow the manufacturer’s usage directions and safety precautions listed on the product label.
- Use clean, dry measuring equipment for chemicals. Rinse all measuring equipment after using. As a reminder, be careful to never mix different types of chlorine together. Also, never let different chlorine product containers come in contact with one another as this is hazardous.
- Store chemicals according to the manufacturer's instructions. Never store different types of chlorine chemicals together.
- Never return spilled material to the original container or place in the household garbage.
- Don't mix spa, pool or household chemicals together.
- Always add chemicals to water, not water to chemicals. Adding water to chemicals contaminates the entire container.
- Don't allow dry chlorine to become damp or wet.
- Keep open flames away from pool chemicals.
- Don't reuse empty containers. Discard any unused chemicals after closing your pool. Follow local ordinances for disposing of hazardous materials.
- Some chemicals have a short shelf life. Check the labels for expiration dates prior to reopening the pool each season. Properly dispose of any chemicals that have expired and purchase new chemicals to replace them.
The Importance of Pool Chemicals
Knowing which chemicals to use in your pool is an important part in keeping the water clean, sanitized and balanced. This is crucial not only for keeping the pool safe for swimming, but it protects your equipment and extends the pool’s lifespan.
Here is a quick reference list of common pool chemicals and their uses:
- Pool chlorine to sanitize the pool water.
- Pool balancers to keep correct levels of pH and alkalinity.
- Pool shock to treat cloudy water and kill off algae.
- Pool water clarifier to help cleanse pool water of dirt and debris.
- Pool algae control to treat green, black and mustard algae.
- Pool salt — used by salt chlorinators to generate chlorine in saltwater pools.
Keeping pool water balanced and sanitized is simple once you know which chemicals to use, how to use them and when. When you test your water regularly, use shock and algaecide as needed and follow safety and storage instructions, you’ll have a pool that’s clean and safe from season to season.
Ready to protect your pool? We have everything you need to open or close your pool for the season. Shop online or stop by your local Lowe’s and pick up everything you need, from pool shock to algae control. Don’t forget to ask a Lowe’s Red Vest associate if you need help finding anything on your shopping list.
Pool Chemicals FAQ
Use the answers to these questions about pool chemicals to help as you treat your pool.
Why do pools need to be treated?
Treating a pool accomplishes several particularly important tasks that make for a safe and enjoyable aquatic time. Pool treatments will ensure that your water is clear and clean and doesn’t have any harmful bacteria, viruses or algae that may cause health problems to swimmers and also damage your pool’s water system. Maintaining the balance between chlorine and pH levels in both chlorine and saltwater pools is key to having a fun day at the pool.
Why is my pool still green after treating it?
It can take several days to as long as a week for green pool algae to clear from your water. You should shock your pool every day until all of the green has disappeared and run the filter constantly until clear. Buildup from metals like copper and excess minerals can also turn water green after pool treatments. Metal, scale and stain products can help reduce and clear discolored pool water.
How often should I test the water?
Pool water should be tested at least once a week; however, test it more often after it rains, during heavy use (like after a pool party) or when the weather is exceedingly hot.