Category Archives: Swimming Pool Chemicals

Shutting down a pool for winter

A huge number of our customers have been regular customers of ours since we began 17 years ago so we assume that they are experienced at closing the pool down for the winter but no matter how many times you have closed your pool down it never hurts to go over the procedure again so you can be sure you haven’t forgotten anything.

The water

You should have had the pH in the correct range but if not now is your last chance. Get the water  to a pH of 7.2 to 7.6 by adding Dry Acid or Soda Ash if necessary.

Kill off any possible remaining algea. Shock dose your water with unstabilised chlorine – raise the chlorine levels to 6 to 10 ppm. Keep your pump running for 6 to 12 hours to distribute the chlorine to all parts of the pool.

Keep the green stuff out for the next few months. Add a winterising product – this is a long life algicide designed to keep your pool free of algae over the winter months. Keep your pump running for 6 to 12 hours to distribute the algicide to all parts of the pool. We like Perfect Super Concentrated Winter Aligicide.

Allow for winter rainfall.  Switch your skimmer valve off and drain the water down to 4 to 6 inches below the bottom of the skimmer. This is to allow for the winter rainfall to bring the level back up otherwise the pool could overflow.

Allow for freezing. Protect your walls from damage by expanding ice by floating something on the water surface to absorb expansion. This can be polystyrene or used chemical containers half filled with water. It is a good idea to tether them around the pool because they can all end up in one corner.

The Covers

Tidy away the summer cover. Take your summer cover off and give it a thorough clean with fresh water. If possible jet it off with a pressure washer but don’t use too much intensity if your cover is quite old. Either fold it up and pack it away somewhere dry or leave it on the roller but cover it over with a winter storage cover.

Keep the leaves out. Put your winter debris cover on the pool to keep as many leaves out as possible. Always tension it as tight as possible. You do not want it dangling in the water. You may need to re-tension it after the first two or three days.

The Equipment

Proctect the expensive stuff. Once you have circulated your chemicals and drained down the top level it is time to drain the water out of your pump, filter and heater. Each should have a drain plug at the bottom to let the water out. This is so it does not freeze inside it and damage it.

Check the water clarity from time to time and if it looks like algae is coming back put some more winteriser chemical in. Despite what they say about lasting 6 months we think 3 months is the duration time for winter alicides.

A review of the Zodiac range of salt chlorination products

This article is about the Zodiac range of salt chlorination products and it is assumed that you know what salt chlorination of a swimming pool is and you are aware of the benefits of salt chlorination. If this does not apply to you then have a read of our article on How Salt Chlorination Works and The Pros and Con of Salt Chlorination

Zodiac are a leading manufacturer of salt chlorination products and dosing systems and we stock four of their products, We will explain here what each of them and how they work together (or not).

The Zodiac EI

The Zodiac EI is a great product. It is an easy to install retro-fit salt chlorinator. It is the entry level, manual control, salt chlorinator and is the only unit most pool owners will need.

The Zodiac TRI

The Zodiac TRI can be retro-fitted but it involves alteration to the pipework whereas the EI does not. The TRI is very easy to install on a new build pool. The TRI purchased on its own works exactly the same way as the EI so if all you want is a basic salt chlorinator then get the EI. The advantage the TRI has over the EI is that you can add modules to the control panel to turn it in to an automatic controller. You can add a pH control unit that will automatically regulate the pH or the “pro” unit will automatically regulate the pH and Chlorine level in your pool.

The Zodiac pH Expert

The Zodiac pH Expert is a stand alone pH dosing unit that can be used on any swimming pool to regulate the pH. If you have an EI unit you could add this product to make sanitising and regulating the pH easy. You don’t have to have a salt chlorinator to use the Zodiac pH Expert

The Zodiac Chlor Expert.

The Zodiac Chlor Expert is  also a stand alone dosing unit and is a bit of red herring in the context of salt chlorinators because you will not need this unit if you have a salt chlorinator. The Chlor Expert regulates the Chlorine level in your pool by injecting liquid chlorine when required. So a pool without a salt chlorinator could be fully automated by installing this unit as well as the pH Expert.

We hope that this article has given an insight into the four Zodiac product that we sell but if you have any questions then please call our experts on 0800 690 6288

Keeping Cool & Staying Safe This Summer

Last month brought us a wave of unsettling news stories and media warnings as to the dangers of being a weak swimmer, and the risks of drowning across the nation. Make sure that you and your family are kept safe this Summer while you beat the heat by brushing up on your swimming skills.


Swimming lessons are a compulsory part of primary school education today, with children in Key Stage 2 (aged between 7 and 11) required to be able to swim unaided for at least twenty-five metres. Despite this statutory requirement of the National Curriculum, it is still speculated that one in every three primary school leavers is unable to swim. Research conducted by breakfast cereal giant Kellogg’s, in association with the Amateur Swimming Association, has revealed that 200,000 students will finish year 6 this year without the necessary training to swim safely unassisted.


Of these children, 80,000 will not even have been offered swimming lessons.


Swimming Pool Safety

Teaching them to enjoy the water safely is one of the best gifts you can give your kids

This lack of concern shown for the importance of teaching kids to swim is contributing to a worrying rise of drowning-related deaths. Every year, the United Kingdom loses over three hundred children younger than age five in swimming pool accidents – with over three thousand others ending up undergoing emergency treatment following a narrowly-averted tragedy.


Keep your kids safe this summer – enrol them in a swimming class, if they’re young or inexperienced in the water, and speak to the headmaster or headmistress of their primary school, to confirm that swimming lessons are provided for students. Most importantly, though, never leave young children unattended in (or even near!) a swimming pool.


Children can drown in less than two inches of water, and may be unable to raise the alarm, if you are too far to see what’s going on. Never allow children to be left alone near a swimming pool, unless the pool is completely inaccessible (behind a fence or a locked gate, etc.)


But kids will be kids – and in case your little ones do manage to slip past you into the swimming pool area, keeping some basic but essential supplies close at hand down by the pool can avert disaster. Ring buoys are a flotation device that can be thrown to toddlers (or any swimmer) in trouble to prevent them sinking below the surface, and a reach pole is used to pull struggling swimmers to the side.


As vital as it is to teach children of the dangers the water can pose, it’s equally important to teach them not to fear swimming unduly. Splashing around in a pool is one of the greatest and simplest joys a child can experience, and swimming is a skill that can be of huge benefit later in life. It would be a great shame to have that experience go to waste.

swimming pool winterisers – a cost comparison

Every autumn pool owners buy their winterising chemicals but how many of them study the label and take note of the recommended doses?
Winterising chemicals can come in 5 litre, 3 litre, 2 litre or 1 litre bottles and they all have different pool volumes that they can dose.
Despite what it may say on the lablel, winterisers will last for about 3 months so to get 6 months of protection you will need to dose your pool twice. Once in October and again in January.
The contents are mostly water with the “good stuff”, the algicide, in varying concentrations. So to cut through the confusion we have come up with our pound cost dosage comparison. We have standardised our pool volume to 10,000 gallons and our longevity to one 3 month span.
You don’t have to use winter algicide, some summer algicides will do the winterising job just as well so we have included them too.
Reading across the table Perfect Super Concentrate comes in a 1 litre bottle and will treat 26,000 gallons. That means you need  0.4 litres to treat 10,000 gallons. At a cost of £24.00 for 1 litre that means it costs £9.60 to treat 10,000 gallons. Compare that to the popular Kleen Pool Brand and you’ll see it costs £22.50 to treat 10,000 gallons.  Worse still is Clear n Clean at £33.60 per 10,000 gallons.  That is why we don’t sell them!
Chemical name Container size Gallons container will treat Litres required to dose 10,000 gallons Container
Cost per 10,000 gallons
Perfect Super Concentrate 1 litre 26,000 0.4 £24.00 £9.60
Champion Winterclear 5 litres 12,000 4.2 £21.00 £17.64
Blue Horizons Wintertime 5 litres 15,000 3.3 £27.00 £17.82
Fi-Clor Winteriser 3 litres 19,000 1.6 25.00 £13.15
Kleen Pool 1 litre 5,000 2.0 £10.25 £20.50
Clear n Clean 1 litre 6,000 1.6 £21.00 £33.60
Blue Horizons Algimax 2 litres 20,000 1.0 £26.00 £13.00


We sell the top 3 on the list. Two dedicated winterisers (Perfect Super Concentrate and Fi-Clor winteriser) and the all year rounder Blue Horizons Algimax Eliminator.

What is Available Chlorine?

On the label of most swimming pool chlorine products you will see a reference to “Available Chlorine”. This short article will attempt to explain what that is.

In its natural state of 100% purity chlorine is a gas but  swimming pool chlorine is often refered to as “granular chlorine” or “shock chlorine” or “chlorine tablets” “or “liquid chlorine”.  In order to get from a highly poisonous gas to a stable white powder you have to add stuff. The more stuff you add the lower the content of chlorine becomes until it is low enough to remain stable in the container and for general handling.

Chlorine Tablets contain chlorine in the form of trichloroisocyanuric acid (short name “trichlor”). This is the most concentrated form of swimming pool chlorine with a 90% available chlorine level.

Next comes Shock Chlorine which is calcium hypochorite (short name “cal hypo”). The strength of this can vary, as a minimum it is 65% available chlorine, but some of the fi-clor  superfast blends are 75% available chlorine.

Granular chlorine has a few different chemical names but is best known as sodium dichloroisocyanutrate (short name “dichlor”). This has 55% available chlorine.  Granular chlorine and chlorine tablets contain cyanuric acid which is a stabliser to stop the chlorine being burnt off by the sun.

Liquid chlorine, like shock chlorine, does not contain cyanuric acid stabiliser. Liquid chorine is sodium hypochlorite and contains about 15% available chlorine. Other forms with 10% or lower concentrations are available and are used by dairy farmers for sterilisation and in household bleach.