See-through - Neptune-Benson

The voice of the Wet Industry 

www.splashmagazine.com.au 

February/March 2010 

See-through 

POOLSACRYLIC 

VIEWING PANELS 

FINER FILTERS 

Improving efficiency 

CBD POOL 

On the Yarra 

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industry feature 

The crystal clear water of Murwillumbah Pool, 

which uses filters featuring Zelbrite filter media. 

Finer filtration 

Media matters in 

swimming pool filters. 

F 

iltration is one of the key components 

of a sanitisation system necessary to 

provide safe clear water for swimmers 

to enjoy. 

The most common types of filters use 

filter media (most commonly sand). In this 

article we’ll be mainly looking at the different 

types of media used in filters, in both the 

residential and commercial environments. 

To start with, John McKenny, instructor 

and author of the Easy-to-Unde rstand 

Leisure Pool and Spa Handbook, has given 

us a quick rundown of the different type 

of media and filters. Further in the article, 

we will get more specific information from 

the manufacturers of some of the types of 

filter media. 

Sand 

(a) Graded filter sand – By far the most 

common media used. It is readily available 

and transported in bulk bags or easier-tohandle 

25kg bags. It’s washed and graded 

and quite course compared to normal beach 

sand. Although reasonably cheap to buy, 

transport costs can make it expensive. It is 

32 | SPLASH! www.splashmagazine.com.au 

known to last many years. Sand in gravity 

filters fifty years old is common. It can be 

regularly cleaned using common liquid soap 

during a backwash, to assist in removing accumulated 

fats and oils, but regular removal 

of the surface layers is recommended to 

properly remove any build-up of salts from 

the pool water and sanitisers. In small pools 

such as private installations, a periodic acid 

rinse during backwash can assist; but great 

care is necessary to protect equipment, 

persons and the environment. 

(b) Ultra-Fine Sand – Ultra-fine sand 

use in swimming pool filtration is so far 

limited. It is used in other areas, often in 

conjunction with additional equipment such 

as centrifuges, to produce high quality air 

and sometimes water, filtering down to 

less than one micron (one micron = one 

millionth of a metre). [Care should be taken 

handling dry ultra-fine sand due to potential 

health risk from inhalation.] 

Sand replacements 

(a) Zeolite – There are several brands and 

grades on the market. Generally, those who 

have experienced operational difficulties 

using zeolite have used an inferior (imported) 

product. Good quality Australian zeolite gives 

excellent results. It is simply substituted 

into any “sand” filter and provides an almost 

instant improvement in water cleanliness, as 

it is claimed to filter down to approximately 3 

microns. Although slightly dearer than sand, 

it enables less total chemical use, water consumption 

and heat loss, as times between 

backwashing is often halved. 

(b) Glass – Crushed glass can effectively 

filter water, having similar properties to its 

close relative, sand. Manufacturers advise 

that this recycled glass is superior to normal 

sand, as it provides better cleaning of the 

water and requires less backwashing, saving 

on water, heat and chemicals. 

Other filtering methods 

(a) Cartridge filters – These are common in 

small installations. They are usually cheaper 

than sand filters for the same pool size, 

easier to install and use less water when the 

filters need cleaning, as opposed to sand filter 

backwashing which can use considerable


Diamond Kleen filter media 

quantities of water and therefore lose larger 

amounts of chemicals and pool water. 

(b) Diatomaceous earth filters (DE) – 

Proven to be a reliable method of effectively 

filtering small to large quantities of water 

for both swimming and drinking. DE, in 

the form of fine powder, is introduced into 

the flow system to form a barrier to all 

impurities including bacteria and pathogens 

such as giardia and cryptosporidium. 

Its drawbacks are that as well as being 

sometimes a bit expensive, the DE powder 

is considered unsafe if inhaled. Its disposal 

after backwashing requires special care. 

(c) Perlite – This natural substance is 

processed and crushed to a powder and 

used in a similar way to DE. According to 

those who have used and are still using perlite, 

it can be easily backwashed and doesn’t 

require cleaning, and therefore replacing, as 

often as DE. [However, some large commercial 

systems use no backwashing and simply 

replace the media]. 

(d) Granular Activated Carbon (GAC) – 

Already used in de-ozonation chambers 

where ozone units are in use, GAC can 

effectively remove almost all substances in 

the water, including tastes, colours if any, 

sediment and even chlorine and similar 

added chemicals. Some GAC compounds 

with special alloys added can filter out all 

substances, including cryptosporidium, 

giardia and other pathogenic bacteria. 

(e) Cellulose fibre – This is used in openstyle 

filtering for large commercial projects. 

Additionally, pre-filters such as MultiCyclone 

can be used to increase filter efficiency 

and reduce the backwash requirements. 

There are also other types of filtration 

that are mainly used for water treatment 

industry, such as reverse-osmosis filtration, 

in which the water is forced under pressure 

through a semi-permeable membrane. This 

type of filter is used in desalination. 

Glass filter media 

Dan Kwaczynski of Poolrite, manufacturer of 

Diamond Kleen, gives us a rundown on glass 

filter media. 

There are many forms of filtration available 

to the market – DE, sand, zeolite, recycled 

glass and more. In this short section, I will 

focus on the performance of recycled glass, 

(specifically Diamond Kleen) compared to the 

performance of sand and other media. 

The first question that must be asked is 

what are we all looking for in a filtration 

media (excluding price which we naturally 

all care about). Here are some parameters, 

by no means exhaustive list – pressure difference, 

level of cleaning (micron rating), 

water saving (time between backwashes and 

backwash duration), environmental footprint 

and longevity/maintenance. 

Cleaning ability/micron rating 

The primary mechanism by which sand 

and zeolites catch particles is by mechanical 

entrapment. This is based on 

the porous nature with particles caught 

in the gaps. Zeolite is far superior to sand 

in this regard and cleans to a high level – 

less than 10 micron. The performance of 

sand, which has a less porous structure, 

will naturally be worse than this, perhaps 

filtering to 15-20 micron. Diamond Kleen 

has a completely different entrapment 

mechanism yet still manages to perform to 

well below 10 micron. Research has shown 

that this primarily relates to an electro 

charge that attracts particles. In fact, glass 

media is not very porous at all and is actually 

quite smooth on the surface. Why is 

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10 micron an important parameter? This is 

generally believed to be the visible range, i.e. 

below that and the water will look beautiful, 

above and it won’t be quite as clear. 

Pressure difference 

The pressure difference is an important 

parameter because this relates to the size of 

pump and the flow rate delivered (and from 

this, current draw and carbon footprint). 

Porous media will generally have higher 

pressure differentials because the water 

flows into all the particle gaps, cracks and 

pores. By comparison, glass media’s smooth 

surface allows water to pass more easily, 

hence reducing the pressure loss, and making 

the filter more energy efficient. 

Another key factor in the performance of 

a media is the grading – both in terms of the 

minimum and maximum particle sizes and 

the spread of media across this range. For 

example, too large a grading range and the 

smaller particles fill the gaps left between 

the larger particles leading to higher differential 

pressure and easier clogging. Too 

small a grading range or gradings that 

are too fine can lead to quicker clogging 

and therefore quicker pressure build up. 

Diamond Kleen has been specifically engineered 

to optimise this delicate balance, 

using a highly technical manufacturing process 

which includes particle activation. 


Water saving 

The water saving ability of a media is based 

on two parameters – the ability of the media 

to hold waste without increasing pressures 

and the time taken to backwash once pressure 

has been built up. There is currently 

independent research to verify exactly these 

two water saving measures for both Diamond 

Kleen and zeolite. Both Zelbrite (a brand 

of zeolite) and Diamond Kleen have been 

awarded the Smart Approved WaterMark. This 

is an independent organisation that validates 

the water saving capabilities of products. 

From experience, both Diamond Kleen 

and zeolite have excellent waste holding capacities, 

albeit that zeolite requires recharging 

at intermittent frequencies (in order to 

clean out all the pores). This is not really 

surprising when you consider the entrapment 

mechanisms mentioned above. 

The other parameter to consider is backwash 

duration. Given zeolite and sand use 

mechanical entrapment, it is clear that the 

more deeply embedded particles are in the 

structure, and so the longer the backwash 

time is needed to completely clear these 

particles from the porous structure. By comparison, 

glass backwash durations are usually 

significantly reduced as the particles are held 

loosely on the smooth surface of the particles. 

Longevity and maintenance 

The limitations of sand are that is breaks 

down over time, while zeolite requires 

recharging and replacement. Recycled glass 

media, by comparison, has a much longer 

life expectancy due to the increased hardness 

of the material. This can be further 

broken down to separate clear sheet glass, 

which has a relatively low smelting temperature 

and hence lower hardness reading 

compared to bottle glass which has higher 

smelting temperature and higher hardness 

reading. It is therefore expected that glass 

media (recycled or new) using bottle glass 

will last longer than sheet glass. 

Environmental impact of production 

Zeolites, sand and new glass require quarrying 

operations to produce the base material. 

This not only digs into our natural environment 

but also uses significant energy to 

dig, convey, process, sort, ship, and bag the 

product for market. New glass is even worse 

– requiring large amounts of heat to melt 

the product and transform it into glass. 

Recycled glass media is by far the lowest 

environmental impact of production. There 

is no quarrying and there are no holes being 

dug in the landscape. It uses existing material 

that was previously destined for landfill, has 

been saved and re-used. So in reality, for every 

tonne of recycled glass used in filtration that 

is one tonne of landfill saved – and potentially 

many tonnes of quarrying saved (depending on 

the yields of production for sand and zeolite). 

The Australian market has embraced the 

use of recycled glass media. It is interesting 

Zelbrite filter media in sizes 0.5 to 1.0mm (x200) 

that only now other markets in the world are 

starting to see market growth in recycled glass 

media, even though glass media per se has 

been used for filtration for many years (there 

are even reports that recycled glass was used 

more than 20 years ago on Hamilton Island 

when no sand was available at the time). 

For more information go to www.poolrite. 

com.au. 

Australian zeolite 

Peter Rabbidge of Zeolite Australia, manufacturer 

of Zelbrite, talks about zeolite in 

general, and Australian zeolite in particular. 

Zeolite is a natural mineral found in many 

countries around the world and is the result 

of volcanic activity. 

Not all zeolites are the same. For example, 

the zeolites found in Europe, Asia and 

New Zealand are very soft and therefore not 

suitable to be used as a filter media. These 

are mainly used as adsorbents such as Kitty 

Litter and for soaking up oil spills. 

Zelbrite’s zeolite is mined at Werris Creek 

in Northern NSW and is one of the hardest 

zeolites found in the world. This filter media 

was introduced to the Australian swimming 

pool market approximately 10 years ago and 

has been used throughout Australia in both 

backyard and commercial pools. It has been 

exported around the world and Zelbrite has 

recently been selected as the zeolite filter 

media of choice by AstralPool in Spain. 

Many people have made many claims and 

sometimes their claims do not come from 

independent testing. For this very reason, 

Zeolite Australia chose to have Zelbrite 

tested by the Australian Water Quality Centre 

(AWQC) whose test results showed it would 

give the performance of DE with the convenience 

of sand. In the past DE has been held as


Right: Perlite media under magnification 

Above: Perlite media under 100 times closer magnification 

the benchmark for filtration: that is, DE to 5 

microns, while sand only filters to 15 microns. 

The AWQC test showed Zelbrite could remove 

particles as small as 2 microns. Apart 

from its superior physical properties, it is 

also chemically active removing ammonium 

by ion-exchange, resulting in less need for 

ancillary chemical requirements to maintain 

water quality. 

Being a crushed rock it has a very large 

surface area and therefore during summer 

it will take eight to 10 weeks to reach 

backwash pressure, and secondly it takes 

half the time to backwash as it roughness 

causes it to swirl around inside the filter 

shedding the dirt in half the time. 

Zelbrite is the only zeolite filter media to 

be awarded the Smart Approved WaterMark 

and also recently gained Savewater approval. 

For more information go to www.zelbrite. 

com.au. 

Perlite filter media 

Perlite is another type of pool filter 

media, used pretty much exclusively in 

large commercial applications such as 

water parks. Neptune-Benson’s Defender 

36 | SPLASH! www.splashmagazine.com.au


regenerative media filters are the main 

type of filters capable of using perlite, and 

applications include WhiteWater World on 

the Gold Coast. 

David Biber from Australian Perlite 

outlines the benefits of the media, and in 

particular the Australian product. 

Perlite is an important filtration media used 

in the clarification of beverages including 

beer, wine and fruit juices and in swimming 

pool and other water filtration applications. 

Perlite is a generic name for a naturally 

occurring siliceous volcanic rock. A unique 

property of perlite is that it expands up to 

twenty times its original volume when it is 

heated to its softening range. 

This expansion process is caused by 

the presence of water in the crude rock. 

When perlite ore is rapidly heated to above 

850°C, this water vaporises and causes the 

softened rock to expand. Tiny glass-like 

bubbles are produced which account for the 

light weight and exceptional physical properties 

of expanded perlite. 

It is these lightweight glass-like bubbles 

that are milled and classified under 

stringent quality controlled conditions 

to produce perlite filter aids. This material 

exhibits a unique, jagged interlocking 

structure with myriad microscopic 

channels affording optimum flow rates 

and clarities for a wide variety of applications. 

Perlite filter aids do not impart taste, 

colour or odour to liquids being filtered and 

they are virtually insoluble in mineral and 

organic acids at all temperatures. 

Comparative products such as diatomaceous 

earth (DE), sand and zeolite are also 

used in filtration. DE does have high crystalline 

silica levels and accordingly it is listed 

as a potential carcinogen and a Dangerous 

Good (DG) under UN protocols. 

DE, sand and zeolite are much heavier 

than perlite and for a product that is sold by 

the kilogram this makes it a more expensive 

option than perlite (perlite is at least 30 per 

cent lighter than any of these options). 

Because perlite stays in solution, it can be 

easily and legally disposed of in municipal 

sewers while DE requires removal to a DGcertified 

land fill. 

Australian Perlite (Ausperl) is the primary 

supplier of perlite filter media in Australia 

and New Zealand. Products are matched 

to client requirements. Manufacturing 

takes place in Sydney where a disciplined 

testing regime ensures that the product is 

highly consistent. Due to the bulk density of 

perlite, local supply is likely to be the most 

economic choice. 

For more information go to www.ausperl. 

com.au. 

RMF and perlite 

in water parks 

June Holaday from Neptune Benson, 

manufacturer of Defender filters, explains 

the benefits of regenerative media filtration 

(RMF) in large commercial applications such 

as waterparks. 

When it comes to waterparks, one of the 

toughest obstacles to overcome is public 

perception. The visitor sees what appears to 

be an endless stream of water flowing all over 

the park. What they don’t see are the very strict 

measures that parks take to conserve water 

behind the scenes. On average, a 100,000 

square foot (9300 square metre) waterpark 

resort might use 125,000 to 160,000 gallons 

of water per day (473,000L to 600,000L). In 

comparison, golf courses in the United States 

noise! 

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fencing and licensing legislation, and training and career pathway development. 

That’s why we’ve designed a new licensing program in collaboration with 

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And if you become a SPRAA member you’ll receive a $500 discount*. 

Join today at www.spraa.asn.au and 

discover the benefits of membership. 

*Conditions apply after 31st December, 2009. 

www.splashmagazine.com.au SPLASH! | 37


Right: The Neptune Benson Defender 

Above: The AquaBoss open filter tank using Purifibre 

consume an average of 300,000 to 500,000 gallons 

of water per day (1.1ML to 1.9ML). Though 

most people don’t seem to associate golf 

courses with excessive water consumption. 

New technologies are being implemented 

throughout waterparks to reduce, reuse and 

recycle water. One of the key elements is the 

use of regenerative media filters (RMF) such 

as Defender instead of high rate sand filtration. 

This popular filtration system requires 

no backwashing, saving up to 90 per cent of 

wastewater and eliminating the need for a 

backwash holding tank. 

The RMF technology operates on the 

premise of surface filtration, has tremendous 

Smart Approved Water 

Mark favours four 

filtration products 

SMART Approved Water Mark, 

the not-for-profit program that 

helps consumers make informed 

choices about saving water around 

the home, garden and pool, has 

included four swimming pool 

filtration products. 

Two are filter media – Zelbrite 

zeolite media and Poolrite’s 

Diamond Kleen recycled glass 

filter media. 

The other two are Waterco’s 

MultiCyclone pre-filter and Ian 

Coombes’ AquaBoss commercial 

swimming pool filter system. 

Products and services with the 

Smart Approved WaterMark label 

have been assessed by an independent 

technical expert panel. 


dirt holding capacity, which extends filter 

cycles to weeks or even months. The reduction 

in backwash water also means that less 

‘make-up’ water needs to be reheated and retreated 

with chemicals. Operators report over 

30 per cent savings on chemicals and heating 

fuel which helps reduce the carbon footprint. 

Additional features that reduce the carbon 

and water footprints are reduced electricity 

usage and saving on construction room. 

Regenerative media filters operate at a 

lower head (TDH) compared to traditional 

sand filters, saving motor horsepower. When 

paired with a variable frequency drive (VFD), 

electrical usage may be cut up to 30 per 

cent. The RMF mechanical footprint requires 

less than one-quarter of the space occupied 

by sand filters, which significantly saves on 

construction costs. 

Since so much more waste water is being 

eliminated, it becomes critical to maintain 

optimum pool water quality. Regenerative 

media filters can remove particles down to 

1 micron. This allows for more than 99.9 

per cent of cryptosporidium to be removed 

in a single pass. The superfine filtration 

of the water also increases UV sanitation 

efficiency. So an additional benefit is that 

a regenerative media filter combined with 

a UV sanitation system becomes the best 

defence against recreational waterborne 

illnesses (RWIs). 

Australia, suffering its worst drought in 

a century, is home to WhiteWater World in 

Queensland. According to Angus Hutchings, 

the park’s Environmental Manager, the regenerative 

media filtration has the most impact 

on their water conservation. They use 90 

percent less water and save approximately 23 

million litres of water per year. Additionally, in 

an independent, third party water efficiency 

audit conducted by Environmental Resources 

Management Australia (ERM), WhiteWater 

World has been given the highest efficiency 

rating possible for a waterpark. 

For more information go to www.DefenderFilter.com. 

Commercial filtration with 

cellulose fibre 

Ben Coombes from commercial filter manufacturer, 

Ian Coombes, describes a new 

form of filter media – cellulose fibre. 

AquaBoss fine media filters use the vacuum 

media filtration principal. They operate 

by drawing the water through an open tank 

full of filter elements. Each filter element is 

coated with a cellulose fibre called Purifibre 

which is a non-toxic, non-carcinogenic media 

that provides filtration down to 2-3 microns. 

This level of filtration is comparable to 

diatomaceous earth without the unwelcome 

handling issues. Purifibre is made from 

wood pulp just like paper. This makes it a 

safe and user-friendly product to work with. 

It is a renewable resource and is 100 per 

cent biodegradable allowing it to be discharged 

direct to the sewer without the need 

for large backwash holding tanks. 

AquaBoss filters in conjunction with Purifibre 

can give filter cycles of eight-to-16 weeks, 

therefore using minimal water in comparison 

to other filtration types. AquaBoss filters 

require 3000 to 9000 litres per backwash, 

compared with 10,000 to 15,000 litres used by 

a conventional sand filter system. 

The filter shell is open to the environment 

which makes trouble shooting quick 

and easy as the filtration process is clearly 

visible. This also has the added benefit of no 

pressure in the filtration tank resulting in a 

long product life. 

For further information go to www.iancoombes.com.au.

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