Category Archives: Swimming Pool Filtration

What is the right sand for a swimming pool filter?

If you have a swimming pool filter then the likelihood is that it is a sand filter. As the name suggests a sand filter uses sand to filter the impurities out of the water. Sand is put in the filter vessel and the water is forced under pressure through the bed of sand. The water molecules pass through the gaps between the sand grains but solids in the water are held back in the gaps between the grains.

You cannot use just any old sand in a swimming pool filter it has to be a special refined grade of sand known as 16/30 grade. The numbers refer to the size range of the grains in thousandths of an inch. In 16/30 grade sand the smallest grain will be 16 thousandths of an inch, there should be no grains smaller than this. The largest grain will be 30 thousandths of an inch, there should be no grain bigger than this.

This type of sand is not usually kept in stock in builders merchants or DIY superstores but you can buy it from PoolStore. It comes in 25 kg bags and a typical filter requires 6 or 7 bags. Rather than load them all in your car, we can deliver them to you door the next working day.

It is essential to use the correct sand in your pool filter

If the grains of sand are smaller than 16thou they will pass through the laterals at the base of the filter and end up back in your pool. If you see sand grains in your pool then it is probable that they have come out of the filter either because the grains are too small or because the laterals in the filter are broken.

If the grains are bigger than 30thou they will be too big to catch the fine solids in the water.

After a while the gaps in the sand fill up with dirt from the pool and you have to “backwash” the sand by forcing the water through it in the opposite, upwards, direction. This loosens up the sand allowing the dirt to be washed out and then you can restart the process again.

Click here to purchase 25kg bags of 16/30 grade sand

MultiCylone Plus blows a wind of change through pool filtration

Every year, every manufacturer claims to have produced a revolutionary new product that will change the way we look after our pools and on closer scrutiny they are just a reworking of an old product but the Multicyclone Plus is a genuine new product and we are very impressed by it.

New products that are a big improvement on what was there before are quite rare in the pool industry. The only two of note in the past few years were Sea Klear clarifier and the Nirvana Heat Pump. Now we can add the MutliCylone Plus to that very short list.

The MutliCylone Plus was developed from the MutliCylone which is a device that is placed in the pipework before a sand filter. It uses centrifugal force to pre-filter out about 80% of the dirt and so gives the sand filter much less work to do. The MutliCylone Plus takes the idea to the next logical level. If 80% of the dirt is gone then a paper filter can handle the remaining 20% quite easily. So a paper filter was placed on top of the MutliCylone and the MutliCylone Plus was born.

The technology inside the MutliCylone Plus is the same as is inside the Dyson carpet cleaner. Dyson have the patent for this technology for use in air, Waterco the manufacturer of the MutliCylone Plus have the patent for its use in water.

The MutliCylone Plus - a revolution in pool filtration

The pool water enters at the bottom and then goes through a bank of cyclones causing a vortex from which the dirt is spun out and gathers in the sediment bowl. From there the water goes through the paper filter which catches all the fine dirt that was not spun out. When the sediment bowl needs emptying just open the purge valve and only 15 litres of water is required to wash it out. The manufacturers claim that paper filter cartridge needs cleaning every 6 months but we recommend cleaning it every month or so with instant filter cleaner.

The advatages of the Multicyclone Plus include

  • It is much cheaper than a sand filter
  • It takes up much less space in your pool room than a sand filter
  • It is easier to maintain than a sand filter
  • No backwashing means a saving of thousands of litres of water
  • No backwashing means not having to heat up fresh water used to replace the backwash water
  • It is easy to install
  • No costly and time consuming sand changes.

So there must be some disadvatages to the MutliCylone Plus? Well, one big disadvatage is for the pool trade is that no filter sand changes are required so many will be reluctant to push it because it does them out of a lucrative source of work in the winter. The largest version of the MutliCylone Plus is big enough for a 75m3 pool. That is not particularly big, about a 10m x 5m or 16ft x 32ft pool. So owners of larger pools will not be able to use one on its own. Waterco do plan to develop the technology for bigger pools including comercial pools also though.

All in all we think this is a very good new product and are happy to promote it.

Installation is relatively simple. Typically you would install it directly above the outlet of your circulation pump. In the picture below a Salt Chlorinator is attached above it but in a normal installation a couple of 90 degree bends would take the pipe vertically downwards and back to the swimming pool return line. It is not very heavy and the pipes will support its weight. Alternatively there is a stand for it to sit on the ground.

The Multicyclone plus is typically installed directly above the pump outlet

Swimming pool pumps targeted for carbon reduction

From Swimming Pool News, April 2010:

The European pump manufacturing sector has been actively engaged with the EU in developing policies, standards and programmes to make an impact on carbon reduction.

The move has been made through the European Association of Pump Manufacturers. Pumps are responsible for some 5% of total electro-motive energy consumption, and the European pump sector is only too aware of the need to make a significant contribution to carbon reduction.

Under the EUP directive the Commission focussed first on high production volume products, identifying glandless circulating pumps up to 2500W and various centrifugal based water pumps as the initial targets.

Europump via its standards and technical commissions formed an energy joint working group, who with the co-operation of the Technical University of Darmstadt formulated carbon savings programmes and standards for all the associated pump types. The work on the circulators has now been completed with new and tough efficiency improvements due to come into force in 2013 and 2015 respectively. The changes will require massive production investment by the pump sector largely due to a technology shift, which will require a move toward permanent magnet motor technology and variable speed controls. At the same time the EU approved new energy targets for the majority of electric motors fitted to pumps.

Europump are continuing to negotiate with the EU on the water pumps, where their ‘house of efficiency’ scheme is expected to be used in the removal of least efficient products. They are also working toward the development of extended product and systems standards, where the potential for significant carbon reductions are best obtained.

The EU have now informed Europump that Swimming Pool pumps are next in-line, and it is likely that the programmes and standards being developed by Europump will be adapted to fit products in this sector.

The time is fast approaching when pumps fitted to swimming pools, like those used in domestic heating systems, will face stringent efficiency design standards, along with the need to adopt extended product control and monitoring equipment, and to be applied to efficient system design.

The British Pump Manufacturers Association have as the UK members of Europump been at the forefront of the European energy programme; providing experts, secretariat, and working group chairmen all overseen by the BPMAs representative on Europump Council, Ken Hall, Managing Director of Calpeda Pumps, who has been the President of Europump for the past two years. The BPMA is also in negotiations with the UK government in respect of the EUP directive and UK specific legislation.

The New Intex Sand Filter

Intex above ground swimming pools are synonymous with high quality and inovation and 2010 sees the introduction of a product that has been long awaited by many owners of Intex pools – a sand filter.



Up to now all Intex pools came with a combined pump and paper cartridge filter. The pumps are very good and whilst the paper filters pick out the dirt and debris in the water they need cleaning often and should be replaced from time to time.


In ground pools and the bigger above ground pools have sand filters. Sand filtration is the best and easiest way to filter swimming pool water. The water is pumped in at the top of the filter chamber and pressure from the pump forces the water down through a bed of sand. As the water passes through the sand bed the dirt and debris is left behind in the sand and clean water emerges via lateral pipes with fine slots in at the base of the filter. When the filter needs cleaning the water is pumped the oposite way, the sand “fluidises”, the dirt is lifted out and the dirty water is sent to waste. This is called backwashing. Sand filters can hold much more dirt than paper filters and don’t need washing as frequently.


Whilst there are many pump and filter combinations on the market they are all geared to inground pools with standard 1.5 inch solid pipe fittings. The difficulty always was adapting the fittings on them to work with the Intex pipework. The new Intex sand filter solves these problems because it is made to fit directly on to the non standard pipe fittings that are found on Intex pools. It also comes with adaptors to make it fit all other makes of above ground pool.


The filter is easy to assemble and requires just one 25kg bag of  “16-30” grade filter sand.


If you are looking to replace your paper filter with a sand filter then the Intex sand filter is the obvious choice.