What are Swimming Pool Oxidisers and do we need them?

Written By Timothy Te

25th May 2021

In a world where antioxidants are being touted for their health benefits, there’s actually one place where oxidisers and oxidation is paramount, and that is in your pool!

Difference between Sanitising and Oxidising

While they’re a little bit similar, there are key differences between sanitising your pool and oxidising. Sanitising kills algae, bacteria, and other living contaminants in the pool. Oxidizers on the other hand destroy non-living contaminants that make your pool water cloudy.

What exactly is oxidising?

Oxidisers use active oxygen in the water to consume the waste (in the pool’s case chloramines and other “dead” particles) and convert it into gas that gets released into the atmosphere. Apart from chloramines, oxidisers also take care of other waste like microscopic dirt, body oils, dead algae, and other chemical by-products that can’t be caught by your filters and cause cloudy pool water.

Does it sound familiar? Well, if you haven’t figured it out by now, oxidising your pool is just another way of saying that you’re going to shock your pool!

Why is oxidising important?

Keeping your chlorine levels at the proper levels and sanitising your pool isn’t actually enough. The reason for this is that over time, the chloramine levels or combined chlorine (when basing off of test kits) will eventually rise. Combined chlorine does nothing for your pool. In fact, combined chlorine is nothing but chlorine that has been “used up” when they bind with organic material like body oils, dead skin cells, dead algae particles, and other contaminants.

The higher your combined chlorine levels in your pool, the less effective your chlorine is in sanitising your pool. In fact, it’s like a snowball effect. The rise of combined chlorine will increase the more there is in your pool until no matter how much chlorine you’ll add, it’ll remain ineffective! Why does this happen? With enough organic matter in your pool, any chlorine you’ll add will actually form more chloramines instead of hypochlorous acid! This is why a lot of pool owners get confused on why adding chlorine doesn’t work!

Oxidising or shocking your pool will destroy chloramines and will leave your free chlorine to do its job in sanitising your pool.

Signs that you need to oxidise or shock your pool

Whenever you start to notice that strong chlorine smell and your water starts to look cloudy and green then a good shock is in order! Of course, even without these tell-tale signs, a good way to get ahead of the problem is to test your pool water. Once your combined chlorine levels start to reach 0.5ppm then shock your pool asap! Don’t wait until it has reached levels equal to your total chlorine.

Another practice that is very common is to automatically shock the pool after heavy usage, and this is something that we actually think is a good idea. No need to test your pool, just shock it overnight after a pool party and that should ensure that your water stays clear and your chlorine stays effective!

Another way to guarantee that your chlorine stays effective is to shock your pool at least once a week no matter what your combined chlorine levels are! At the very least, if you can’t shock your pool once a week, then at least do it once every two weeks, even if you don’t use the pool.

Chlorine shock vs non-chlorine shock

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Confused on which oxidiser to use? Well, to be absolutely safe, chlorine shock is always the way to go as it will sanitise your pool as it shocks it. Non-chlorine oxidizer or non-chlorine shock will only deal with the cloudiness and combined chlorine levels in your pool so you will need to add chlorine or your sanitiser of choice after shocking your pool with non-chlorine shock

Shocking in the blind vs testing before shocking

A common practice that many pool owners do is that they have a pre-set amount (calculated of course) that’s guaranteed to wipe out any existing combined chlorine in the pool. Is this a good idea? Well, to be honest, yes. Shocking in the blind and following the instructions written on the packaging is an excellent way that you’re getting enough shock in your pool to properly oxidise everything that’s causing cloudy water.

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Testing while shocking on the other hand can get you the exact amount of chlorine shock you’ll need to take care of chloramines in your pool. While it takes a little bit more time to do (testing + calculating how much you need) it does save you a few bucks for every session and over the course of a year, we’d say roughly a couple of hundred dollars saved if you shock your pool with just enough every session.

The choice is really up to you. There’s the easy way of just pouring a packet of pool shock into your pool, saves time, guarantees that everything is oxidised, or saving some money by going the precise way. Either way, it has to be done!

Do you have any questions about this topic or the featured products? No worries, we're here to help! Drop us a question down below and we'll get back to you ASAP.

Happy swimming :)

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Written By

Timothy Te

Pool Guru at Mr Pool Man

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