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What Chemicals Do You Need for a Swimming Pool?
Owning a swimming pool is a fantastic way to enjoy leisurely exercise, relaxation, and family fun in the back garden. But at-home swimming pools also come with other responsibilities.
It's only natural to be confused when first encountering swimming pool chemistry and water maintenance – our guide covers everything you need to know about how to balance your pool water using the correct swimming pool chemicals when getting started initially!
Here at 1st Direct Pools, we supply all the essential chemicals involved in maintaining a clean, safe swimming pool, so we know a thing or two about what's required.
Unbalanced pool water costs a lot of time and money as you'll need to buy more chemicals and repair any damage. If left untreated, your pool could end up looking more like a swamp than a swimming pool!
A lack of chemicals can create an uninviting and unsterile environment, turning the water various shades of green due to algae growth. The water may even develop harmful bacteria and become corrosive, indicated by a cloudy appearance.
Using swimming pool chemicals to balance out the water chemistry of your pool will encourage a healthy, clean pool for you and others to enjoy. This will create the perfect conditions for the sanitising chemical, such as chlorine or bromine, to effectively sterilise the water.
Here, we cover everything you need for a basic understanding of your pool's chemistry, including:
Getting your pool’s water chemistry right means supporting chlorine to do its job. Chlorine is a crucial component in maintaining the condition of your pool as it destroys and prevents algae from forming.
The recommended value for chlorine in a swimming pool is 1-3ppm (parts per million).
Anything more than that is why you might sometimes end up with red, itchy eyes after swimming.
Chlorine can be found in tablet, granule and liquid forms. While it's fairly easy to treat a pool when using chlorine, it can be slightly confusing when choosing from all the types available.
The easiest, most popular option is chlorine tablets. These are placed in a dispenser that will float in the pool, meaning the chlorine will slowly disperse into the water over an extended period of time.
You can add stabilised chlorine granules to the water directly, but we recommend mixing them with (pool or tap) water first to form a solution before distributing them into the pool water.
Liquid chlorine provides a simple solution for maintaining a clean swimming pool. However, it is primarily used for industrial swimming pools where a substantial amount is required.
For the vast majority of swimming pools, we recommend tablets.
Effectively, bromine does the same job as chlorine. You will not require bromine if you have used chlorine and vice-versa.
Bromine will often cost slightly more than chlorine, hence the popularity of the latter. However, that’s not to say that bromine doesn’t have its unique advantages.
Chlorine is an effective cleaner, but it can irritate those with sensitive skin, whereas bromine causes less irritation.Bromine is also comparatively less susceptible to evaporation in comparison to chlorine, making it a popular option for hot tubs and heated pools.
Similarly to chlorine, bromine is available in different forms but we recommend tablets. Please note that bromine tablets will dissolve at a slower rate than chlorine; this is an important factor to consider when balancing and testing your pool water.
Bromine requires a reading of 2.5-4 ppm for swimming pools.
Calcium hardness is another chemical measurement; in this case, it determines how “hard” your water is, or how high the mineral content is. Like with everything else, calcium hardness will need regular readings.
This measurement will demonstrate how much calcium is in the pool – too much will result in a build-up, while too little can cause the water to erode the walls and metal of the pool.
Calcium chloride is the most common chemical used when treating calcium hardness. This chemical is often available in a granular form, which we would recommend adding to the water when the calcium hardness reading becomes too low.
Unfortunately, if the calcium hardness becomes too high, there are no quick-fix solutions or chemicals available to reduce the calcium in the water. The pool may need to be drained, replenished with clean water and then rebalanced.
For pools with a fibreglass or vinyl liner, calcium hardness should be anywhere between 175-225 ppm.
For concrete or plaster pools, keep levels around 200-275 ppm.
Another key aspect of pool maintenance is maintaining the correct pH balance. Balanced pH is what allows chlorine to do its job and keep your pool clean and algae-free.
pH is a measurement of how acidic your pool is on a scale of 0-14. 7 is considered neutral, anything below 7 is acidic, and anything above 7 is basic (or alkaline – more on that below).
Generally speaking, the ideal pH range for swimming pools is slightly above the neutral zone at around 7.4-7.6.
Keeping your pool at proper pH levels will ensure a comfortable experience for swimmers. Low pH can lead to a whole host of problems, including:
Chances are, everything touching your pool water is subject to acidic damage. Not only will repair or replacement costs need covering, but you also have to keep pool safety in mind.
Swimmers will likely experience dry skin and a burning sensation in the eyes in a pool with low pH.
Alternatively, there are also downsides if your pool’s pH levels are too high. For example, the water may become cloudy with an unpleasant scaled surface.
Algae is far more likely to develop in these conditions, and chlorine is far less effective if pH levels are over 8.2.
Total alkalinity (or TA) is another element that affects the chemical balance of your pool water, as it is closely related to pH.
The desired alkalinity range is 80-120ppm.
Unbalanced TA levels have a domino effect. If the reading is outside of the required range, the pH balance will be affected, which will then go on to unbalance other chemical readings of the pool.
Similarly to pH, low TA levels lead to acidic damage, whereas high TA levels reduce chlorine effectiveness and the overall cleanliness of your pool.
Although TA shares these similarities with pH, keep in mind that they aren't the same thing. Think of TA as a “pH buffer”.
For example, low TA levels can cause rapid pH fluctuations and high levels can make pH levels difficult to adjust as they will increase even if you regularly use a reducer.
It’s important to test your pool water regularly and check that your pool chemistry is balanced.
To make sure the chemicals in your pool are balanced year round, you need to test the dosage around two to three times weekly.
There are multiple ways of testing the balance of your pool water. Browse our range of test tablets for an affordable, easy and effective method of pool testing.
Another method is using test strips. For highly accurate results, we recommend using aquachek yellow test strips. With 50 test strips, this product is a cost-conscious and long-lasting way to test your water. The components they test for include:
By far, the most accurate readings you will get are from photometers and testing kits, although this is more costly.
Adjusting the levels in your pool can be a frustrating and lengthy process, especially if you’re a beginner to pool maintenance. Don’t worry, we’ll guide you through the steps. For an in-depth look, you can read our guide on how to balance your pool.
Use your testing equipment to get an accurate reading of your pool’s levels and keep them on hand as you will need to retest before adding more water balancers to see how they are affecting one another.
We recommend adjusting TA first and then pH, not both simultaneously.
Before adjusting your pool’s chemistry, you need to check the instructions on every product you use.
pH levels can be affected by the following things:
You can resolve low pH with a pH increaser, the most common of which is known as Soda Ash or Sodium Carbonate. These products are often available in powder form and are easy to use.
Conversely, if your pH levels are too high, pH reducer works along the same lines as pH increaser, just in a different direction. pH reducers are often known as Dry Acid and Sodium Bisulfate. These products are commonly in the form of a powder and are easy to administer.
As previously mentioned, TA is a “pH buffer”, so it's necessary to retest water after adjusting TA levels to see how this has impacted pH levels.
Alkalinity increasers, sometimes referred to as TA Plus, often consist of sodium bicarbonate, otherwise known as baking soda. They are available in a powder-based form and used in a similar way to pH adjusters.
Muriatic Acid reduces alkalinity, although this can often be hazardous. Instead, we would recommend using a pH reducer for this task. Be careful as sodium bisulfate will also have the effect of lowering TA at the same time.
It’s best to make small, continual adjustments when reducing the alkalinity and then raise the pH levels until they are both in the proper range.
Keep on top of pool water chemistry with regular testing 2-3 times per week to ensure healthy and safe swimming water.
Shock treatments play an important role in the general maintenance and cleanliness of your swimming pool. These sanitising products are highly-concentrated versions of chlorine or bromine.
If your sanitising chemical levels have depleted substantially, shock treatment will often solve the issue. Shock treatments are also effective at algae or bacteria removal.
Shock treatment should be used after periods of inactivity, even when the water appears to be crystal clear. It is essential to treat the dormant water before using the pool.
Unlike chlorine’s standard counterpart, chlorine shock (which is also known as hypochlorite) will always come in granular or liquid form.
When using these products, the water’s balance can become unstable and deemed unsafe. Therefore, the water will need to be tested and re-balanced again before use.
Sometimes known as a conditioner, a chlorine stabiliser is not necessarily essential, but it can be helpful for certain swimming pools.
Chlorine can evaporate if frequently exposed to the harmful UV rays from sunlight. Stabilisers help to prevent this by using cyanuric acid, which will block the UV rays.
For most UK pools, cyanuric acid isn’t required. It is worth noting that using a chlorine stabiliser is not a substitute for testing the chlorine, pH or alkalinity levels.
When pools become exposed to a lot of sunlight, we recommend regularly testing the water for any alarming reductions in chlorine levels. If the readings indicate this, then chlorine stabilisers can provide a solution.
Clarifiers create a crystal clear pool by polishing the water, causing the tiny pieces of debris in the water to clump together and helping the pool’s filtration system extract them.
Luckily, there are many different swimming pool clarifiers available. Similar to stabilisers, clarifiers make a nice addition to swimming pool setups. However, they are not a substitute for regular maintenance.
If your pool requires a deep clean and depending on the nature of the uncleanliness, you should consider either vacuuming your pool or using a shock treatment.
We hope this guide has helped you make sense of the complex nature of pool chemical balance! Please do not hesitate to contact our expert team at 1st Direct Pools if you need any further pool maintenance advice.
