OC-1 Filter and Media in a Domestic Swimming Pool

Why I chose the OC-1 filter and OC-1 filter media, and how they perform in a domestic inground swimming pool

Pool size 15 mtr X 4.5 mtr Pool shape Rectangular with Roman steps
Pool type Delifol vinyl liner Situation Inground Worcs UK
Capacity 50 cu mtrs/11,000 UK Gallons Use Occasional seasonal domestic
Pump Certikin Swimflo HPS031M Flow rate at 8 mtr head 6.3 cu mtr hr
Filter Certikin ZZOC-1/20 side mount Filter Diameter 20"



I do not sell, or install, or have anything to do with the commercial side of swimming pools, and I have no connection to any manufacturer or supplier apart from being a customer. I am a retired software engineer who inherited a quite badly designed and installed inground pool in the back garden of our house in north Worcestershire UK, and I have fought its idiosyncrasies ever since, not always with success.

I came across OC-1 a couple of years ago, and it gained my interest. Our pool has - or had - a 16" Lacron sand filter which must be around forty years old. Although it takes any kind of abuse it doesn't filter that well and to my extreme annoyance deposits a drift of sand along the seams of the pool liner more or less every day. That's probably more the fault of my backwashing technique than the filter's, but wouldn't it be great if it were impossible for the filter media to migrate into the pool in the first place? When the time came to overhaul the pool equipment OC-1 came to the fore, and I began looking into it in depth. Except that there was no depth to look into. No matter how I varied the search terms, or how many hits I ploughed through, there was not a single review of OC-1 to be found in either domestic or commercial operation. There was the promotional blurb repeated in many sales offerings, and a few short promotional videos on YouTube. But despite that sales blurb claiming that OC-1 has been taking the world of filtering by storm since its inception in 2016, there is not one instance of someone saying 'I use OC-1, and this is what it does.' So this is possibly the first ever independent review of OC-1 in a domestic swimming pool in the world. And at the moment seemingly the only one.

If by any chance these webpages are read by anyone who can shed some light on the areas of confusion, or heaven forfend anyone from Certikin or OC-1 Media, then I shall reproduce their comments here if relevant.

The Pool:

The pool was built around forty years ago, very badly. It is inground, retangular shaped with Roman steps at one end, and has sloping sides and bottom. At the shallow end it's about 750 mm deep, and at the deep end around 2250 mm. It has a skimmer at one end of one side, a suction pipe half way along the same side, and a return pipe diametrically opposing the skimmer on the other side. There is no drain or other pipework. It has a submerged light at the opposite end from the steps. It has had a couple of liner refits, the last one being with Delifol around 2012. It has, or had, a 16" Lacron 406 sand filter and an ITT Marlow 1/3 horsepower pump which have coped for many years. For the last seven or eight years it had an Abrisud low profile cover, which is a godsend in keeping dirt and children out, and the heat in. The temperature can reach over 30 deg C. It doesn't get a lot of use, just two of us in the summer when we can brave the temperature, but with two grandchildren arriving we hope it will be used more. Sanitation is liquid chlorine (sodium hypochlorite) with occasional pH- to lower the pH when necessary. Thw water comes from a spring, and is very hard.

These Pages:

To avoid an endless single page there are separate pages dealing with the reasons why I made particular decisions, and the results that followed. Some of the information here has taken months of internet trawling to dig out, and most of it has taught me a great deal about the mechanics of water filtering. Quite a lot applies to other filtering methods as well. There's no complex maths or graphs, but a few simple sums. I hope it will help others, and as ever comments, corrections and criticism are welcome. Although it is natural, after spending quite a lot of time, effort and money, to look upon your achievements bathed in a generous light, I shall try to be as honest as possible.


Although my natural habitat is feet, yards, pints and gallons I have used the metric system here. Many sites use gallons without specifying whether it is the Queen Anne Wine Gallon of 1707 as still used in the USA, or the UK Imperial measure of 1826, or some other variant. Metric measures can be confusing, but at least the litre and the cubic metre are common quantities wherever you are.


OC-1     Filter     Pump     Progress     Verdict


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If you have any questions, comments or criticisms at all then I'd be pleased to hear them: please email me at kes at kcall dot co dot uk.

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