Swimming Pool Chemicals, Test Strips & Water Testing Kits Products

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Keeping the chemical levels balanced in your swimming pool or hot tub may not be the most exciting aspect of owning one, but it is vital to keeping your water safe for swimming and avoiding problems like murky water! Browse OnBuy's selection of water testing products and swimming pool chemicals today. Read More >

About Swimming Pool Chemicals, Test Strips & Water Testing Kits Products

We have a wide range of water testing products from individual chemical testers and handy all-in-one water test kits to individual swimming pool chemicals and dispensers - ensuring you'll find everything you need to test your pool or hot tub water, and keep you and your loved ones swimming safely. 

If you're new to owning a pool, or have never tested the chemical levels in yours before, read our handy guide to the common chemicals you'll test for to eliminate confusion and help you shop with confidence. Of course, once you've tested the water you'll likely need chemicals to adjust the levels, but don't worry - we have those too! 

Free Chlorine 
We've all heard of chlorine - but why is it important to put in my pool? Chlorine not only kills any lurking viruses and bacteria, but it disinfects the water and removes any organic matter.  Testing kits test for 'free chlorine' which will tell you how much chlorine is left in your pool, and alert you to any changes you need to make to the chemical levels. Once you've discovered you need to add more chlorine, why not check out our handy selection of floating chemical dispensers that will do the hard work for you! 

pH Levels
An ideal pH level for your pool is neutral; somewhere between 7.3ppm to 7.7ppm. Monitoring your waters pH levels is important because if the pH level is too low, you risk damaging your pool equipment (like ladders), and irritating your eyes and skin. Alternatively, if the pH level is too high it can have a negative impact on the chlorine levels, as well as making your water cloudy and irritating your skin. Not what you want when you're trying to unwind in your tub!

Total Alkalinity
Testing kits and strips will tell you the Total Alkalinity level in your water, which should be between 90 and 120ppm to be effective. An essential chemical to test for as it can impact the pH level; too low or high and it'll throw the pH levels off. Low total alkalinity puts your pool water at risk of turning dark and murky, as well as irritating your eyes. High total alkalinity can reduce the effectiveness of the chlorine in your pool, which you'll want to avoid! 

Calcium Hardness
You want to avoid your water becoming too hard or soft - hard water means it has a high mineral content, and soft water means there aren't many minerals. Aim for 200-400ppm to get the water hardness just right. If your pool water is soft (low hardness level), it can corrode the inside of your pool or damage the plaster which may lead to costly repairs! If the water is too hard, you can get calcium build up around the pool which is not only unsightly, it can impact the other chemical levels and result in damage to the pool pump or filter.