Sand, zeolite or filter glass, what to choose for the filtration of a pool?   

The choice of filter medium is very important. It will determine the quality of filtration, the  time to spend on maintenance and the cost. Sand filters are the most popular filtration systems for pools but  they do not have to be filled with sand - there other and better filter materials, with different properties, such as filter glass and Zelbrite (zeolite). To maintain top efficiency, the media must be cleaned regularly so that the bacteria it retains do not clog the filter. This is done by back-washing.

Sand

Sand is the most common filter medium, easy to find and very good value for money, it is the most widespread. However, it only has a filtration fineness of 30 to 40 microns. It offers efficient filtration but requires a lot of maintenance because it can get dirty quickly.

Advantages

• Average filtration, from 30 to 40 microns, relatively sufficient.

• Inexpensive

Disadvantages

• Frequent backwashing, at least once a week,  which loses a lot of water with its valuable chemicals.

• Faster fouling of the filter that needs to be solved by using treatment products (the grains agglomerate with each other and the bacteria create a sticky film reducing performance and producing chloramines)
  

• Agglomeration (clumping) of sand grains and worm-holes causing decrease in performance.

• Lifetime about 3 years before changing

Zelbrite

Made from volcanic material of a kind found only in Australia, Zelbrite (zeolite),  with a filtration fineness of 5 microns offers the best known performance and many benefits. More expensive than sand or glass.

• High filtration of 5 microns.

• Stabilizes the pH

• Helps lower the pH corrector consumption.

• Requires fewer backwashes

• Absorbs AOX, carcinogenic elements naturally present in water

• Limits the formation of chloramines

• Very long life (10 years or more)

• Can be regenerated

• Requires only 75% by weight of the amount of sand

• Backwash only every 8 - 10 weeks

Disadvantages

• Relatively expensive initial investment, from ฿ 640 the 15 kg bag.
  

• Can't be used in conjunction with ioniser disinfectant systems because its filtration is so good it will even filter out the silver and copper ions.
  

Filter glass

Attention: the table below is for 15Kg bags. We sell EcoClear in 25Kg bags.

Filter glass is crushed and graded recycled glass granules from post industrial glass waste. It replaces sand in the sand filter and offers high efficiency and filtration fineness of 15 microns. The fineness of filtration can be improved to 5 microns with a flocculant.

Advantages

• Prevents the formation of a biofilm 

• Reduces the maintenance of the sand filter

• Consumes less water and less treatment products

• Good fineness of filtration

• Ecological life span about 7 years

Disadvantages

• More expensive than sand, from ฿ 700 25 kg

Quick comparison

The pressure gauge: At what PSI should I backwash my pool?

As a general rule, you should be backwashing your pool about once a week or in conjugation with your scheduled maintenance. Another industry standard is to backwash when your filter's pressure gauge reads 8-10 PSI (pounds per square inch) over the starting level or “clean” pressure. Choice of filter medium is very important. It will determine the quality of filtration, the  time to spend on maintenance and the cost.