Everyone dreams of owning a backyard swimming pool and organizing pool parties or swimming in the pristine blue waters whenever the heat becomes unbearable. Simply filling your swimming pool with water will soon turn the color from pristine blue to sickening green. This is from the algal growth and is a sign of your swimming pool turning into a cesspool of contaminations and disease-causing microorganisms. Similarly, the calcium deposits cause lime scales on the pool tiles or acidic content can corrode the metal plumbing and shorten their lifespan.
Along with constant filtration, you need to add certain chemicals to sanitize the pool and keep algae & disease-causing pathogens at bay. While managing the pool chemistry, the big question remains which chemicals to use and how many parts per million (ppm) should it be present for optimum performance? Going through this article, you shall learn about the reasons for pool contamination, the most common pool cleaning chemicals used for specific pool water issues, and mistakes to avoid.
Reasons for Pool Contamination
No swimming pool is safe from contamination as it can happen naturally as well as from regular use. The different types of pool contamination are:
Contamination based on Water Properties
Algal Infestation: Stagnant water can cause algae to set up home on the pool surface and once infested, are very difficult to eradicate.
Calcium Concentration: Similarly, the water in your swimming pool can be from any of the multiple sources and each source has a different water composition. Some may have a high concentration of calcium which can deposit on the pool tiles and make the water cloudy.
Total alkalinity of Water: The total alkalinity of the water is the measurement of carbonates, hydroxides, and alkaline elements in the water. It directly affects the pH levels of the water. Higher concentration means the water is alkaline in nature and will cause sediments to form on the pool surface or pipes & ladders. Lower concentration means the water is acidic in nature and can cause corrosion. The total alkalinity of water is different from the pH of the water.
pH balance: The pH of any substance determines the nature shown by it. Low pH levels (i.e., 0- <7) )indicate acidic nature and higher pH levels (>7 – 14) indicate basic nature. Acids have a tendency to ‘eat’ away surfaces whereas bases have a tendency to ‘deposit’ salts on the surfaces. Either nature can cause skin irritation for those swimming and so it is important to maintain a balance by keeping your pool water at 7.0 pH. While this is not practically possible, experts suggest keeping the water pH at a range of 7.4 to 7.6 pH.
Contamination from External Sources
Natural Contamination: Unless you have an indoor pool, leaves, twigs, and other debris will fall into your pool. Thankfully, those can be vacuumed or filtered out manually.
Body Residues: When someone swims in the pool water, they will leave behind bodily residues such as dead skin, shampoo, soap, oil deposited on the skin, or bodily releases such as urine. Similarly, birds can relieve themselves while flying above the pool. These are breeding grounds for bacteria, viruses, and other microorganisms and if left to flourish, can cause severe skin-related and water borne diseases among the members using the pool.
To counteract every type of pool contamination, you need to add different chemicals in the swimming pool water.
A rundown of different swimming pool chemicals
For the sake of better understanding, we shall divide the chemicals used in the swimming pool into 5 broad categories based on the purpose.
The job of the sanitizing chemicals is to create an unfavorable condition for the microorganisms that kills them and stunts their spread. Swimming pool chlorine is the most commonly used sanitizing agent used in big swimming pools. Chlorine is highly effective and low cost pool sanitizer that oxidizes the contaminants, destroying them from inside out.
They are potent chemicals that can kill most viruses, bacteria, and algae but need to be restricted to 3ppm. Excessive chlorination can cause skin irritation and chlorine poisoning. At such situations, you need to either dilute the water to bring the level low or use a chlorine neutralizer.
Depending on the type of pool you have, you can use two types of swimming pool chlorine:
Used for outdoor pools, these swimming pool chemicals have Trichloro-S-Triazinetrione (Trichlor) which contain 52% cyanuric acid. Cyanuric acid protects the chlorine from direct sunlight, which can burn it off, thereby reducing the chlorine’s effectiveness. Stabilized Chlorine allows the chlorine to stay in the water for three to five times longer.
Indoor pools need not worry about the chlorine burn off and so free radical chlorine or unstabilized chlorine can be used directly. Swimming pool chemicals containing Calcium Hypochlorite are unstabilized chlorine and are a cost effective solution to top up chlorine concentration in the pool water.
The downside of using chlorine as a sanitizing solution for your swimming pool is the formation of chloramines as waste byproduct. Chloramines give the swimming pool that distinctive stench and cause a burning sensation in the eyes. Presence of chloramines is an indication of depleting free radical chlorine in the swimming pool water. The only workaround is to add more chlorine or ‘shock’ the pool water with an abundance of free radical chlorine.
Recently, pool owners have transitioned to using bromine instead of chlorine since bromines take more time to break down and the waste byproduct from using bromine sanitizing products i.e., bromamines have less potent smell and are less reactive to skin. To replenish the bromine level, you still need to ‘shock’ the pool water frequently. Ideally, bromine concentration can be upto 5ppm and shouldn’t go below 3ppm.
For a completely chlorine-free pool, you can opt for Biguanide or polyhexamethylene biguanide. It is similar to hydrogen peroxide and is commonly used as a surgical disinfectant. It works by binding the contaminants into water-insoluble clumps which can easily be filtered out. They are an expensive sanitizer but help you maintain a chlorine-free swimming pool.
2) pH Maintenance
As we stated earlier, the pool water needs to be in the range of 7.4 to 7.6 pH to be suitable for swimming. Any lower and your eyes will experience a burning sensation; any higher and you’ll feel the nostrils dry up. pH of pool water is very delicate and can be altered by anything entering the pool water such as rain water, dirt, people, bugs, etc. Hence, it is very difficult to maintain the pH level and you need to periodically check the pH level and add appropriate pH increaser (basic liquid) or pH reducer (acidic liquid) till you achieve the balance.
3) Alkalinity Management
Alkaline substances such as carbonates, hydroxides in the water affect the pH of the water and prevent the pool pH level from fluctuating. These elements manage to do so by absorbing any major changes to the water before the pH level changes. If you observe the pH level of your water reducing, it is an indication that the total alkalinity of the water is also depleted.
4) Calcium Hardness Control
Depending on where you live, you may have access to water of specific hardness. The hardness of water is defined by the ppm amount of minerals such as calcium, magnesium, fluorine present in the water. The more harder the pool water; the more chances of water becoming cloudy. The less harder the pool water; the more chances of water being acidic and corrosive to the pool surface. The ideal calcium hardness level for your pool water should be 175 ppm to 225 ppm. While controlling calcium hardness, it is important to follow a process. Start with managing the alkalinity, then regulate the pH balance, and finally reduce the calcium hardness.
For addressing cloudy water, use a pool clarifier for a temporary solution and flocculant for clearing the water for the longer run.
It is easy to slip up when it comes to algal infestation and once you have algae growing in your pool, mere chlorination isn’t going to solve the problem. You need to bring out the big gun i.e., the algaecides. Contrary to the name, algaecides don’t kill the algae but restrict its growth until you can bring the chlorine levels back by shocking the pool water twice or thrice. If your pool water is hard, it is advised to go with copper-free algaecide to prevent the pool surfaces from staining.
Mistakes to avoid
- Storing the chemicals in a damp area or in direct sunlight
- Not keeping incompatible chemicals separate
- Not using dedicated tools for each chemical
- Keep new and old chemical together
- Ordering surplus amounts
- Not wearing protective gear while handling the chemicals
You are not a miracle worker. Knowing which chemicals to use is only effective when you know the cause. Unless you manually test the pool water, there is no way to predict the chemicals required til disaster strikes. It is always advised to test the pool water before adding chemicals, and also after adding the chemicals. If you have a good reputation with your local pool store, you can also periodically send pool water samples to have them tested out comprehensively.