Is Glass better than Zelbrite filter media?

Or is it just a myth?

It has been long debated which filter media is best for your swimming pool. Today, 3 major types of filter media exist in the market - sand, glass and Zelbrite. Traditionally, sand filter media has dominated the Australian market, however in the last decade the presence of Zelbrite filter media has become more and more evident. This is because of the superiority of the Zelbrite material. Its sponge-like structure enables it to have a high capacity to filter impurities and particulates, in some cases far better than the glass and sand counterparts.

But it is not just the removal of particulates that your swimming pool requires. Consumers have become increasingly aware of the harmful bacteria and micro-organisms that can grow in their backyard swimming pools if not maintained properly. In addition, with the ever increasing electricity bills, consumers have given more attention to the costs in maintaining swimming pools, in particular with backwash frequencies, carbon footprint, pump sizes and flow rates, media life span, filter sizes, etc. So it is only logical to compare these three filter media based on the scientific data available.

Test against bacteria and micro-organisms

Independent tests have shown that glass and Zelbrite filter media do not have an effect on the growth of bacteria, algae or any form of micro-organisms. A test conducted over 1 month measured the bacterial count of Zelbrite filter media and compared the results to that of glass filter media. These results were similar. Neither glass, nor Zelbrite promoted or reduced the growth of common micro-organisms. They both carry the same amount of bacteria. These results were quite surprising to my eyes. It has been claimed that Zelbrite filter media harbours and promotes the growth of bacteria, but this scientific result conducted by an independent company contradicts these claims. Dr.Prasad of Neptune Bio-Innovations has proven with scientific experiments that both glass and Zelbrite act the same when it comes to bacteria in swimming pools. He further comments that since you cannot differentiate the two media by their properties, Zelbrite would be a better choice as it can filter down to 2 microns whereas glass cannot. This is very important as mobile bacterial species typically range in the size from 1-40 microns so the majority will get trapped by Zelbrite but not by the glass filter media.

Dr Prasad further comments that Zelbrite also assists in keeping the pH neutral. With its unique ion exchange properties, the Zelbrite media can top up the pH, if thereís not enough acid in the pool and alternatively, it can "hold" the acid in the event the consumer adds too much acid. But this is not the case for glass or sand filter media. Unlike Zelbrite, both glass and sand cannot equilibrate the pH to any extent. The right pH is very important, if the pH isnít correct pH 7.4 to 7.6 chlorine becomes very inefficient as a bactericide.

Time and water saving

Consumers are always looking for a filter media that lasts longer can do a good job by reducing backwashing, chemicals and electricity usage.

There are numerous claims as to which of the three filter media has the longest life span. Most claim that sand lasts approx. 5 years whereas Zelbrite will last 10 years plus. Sand over a period of time, grinds with other sand particles in the filter giving it a smooth surface making it less efficient as a filter media. Zelbrite is produced from a volcanic mineral which is much harder than both river and silica sand and even after backwashing it does not breakdown . N.B. Glass is made from silica sand and has a far bigger carbon foot print than both sand and Zelbrite. When glass media comes to the end of itís working life itís disposal is more difficult than Zelbrite which can just be dug into the garden.

Tests show that Zelbrite has a far greater surface area than both sand and glass and therefore has a far greater dirt holding capacity and therefore will double the time between backwashing.

Tests against debris and particulates

Tests conducted by the Australian Water Quality Centre on the ability of each filter media to filter debris and particulates from your swimming pools are indicated in the graph below.

Of the three filter media, it shows that sand can filter down to 15 microns while glass filter media can filter down to 10 microns. What was a surprise was the ability of Zelbrite to filter debris and fine particulates. Test data indicated that Zelbrite filter media could remove particulates down to 2 microns. This means that with the use of Zelbrite filter media, you will have crystal clear swimming pools, virtually debris- and particulate-free. Consumers that have changed over from sand to Zelbrite have noticed the clarity of their swimming pool water virtually overnight.

Zelbrite, once again has proven effective as the filter media of choice for your swimming pools. It has excellent filtration efficiency, does not harbours or promotes bacteria growth, has pH balancing effect, efficiently remove ammonia and most importantly, Zelbrite is environmental friendly. It can be disposed in your garden at the end of its life to act as a fertiliser carrier. Numerous golf courses also use Zelbrite to keep their courses lush and green.


Zelbrite - for Outstanding Swimming Pool Filtration

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