How a Sand Filter Works

Sand is the oldest and most popular method of filtration. Sand filters share two things in common:

  • When in the filtration mode, water always flows from top to bottom
  • They all have some sort of lateral or underdrain with slots to hold back sand while allowing clean, filtered water to pass through.

High-rate sand filters use a special filter sand, normally .45 to .55 mm (also known as pool grade #20 silica sand), because it has sharp edges that separate particles, allowing filtration to take place. They operate on the basis of “depth” filtration where dirt is driven through the sand bed and trapped in the spaces between the sand particles. Initially, a clean sand bed removes larger particles, and then, as the bed starts to load up with dirt, the filter removes finer particles. The sand can be cleaned by backwashing which involves reversing water flow through the filter to the “waste” line. Sand Filters trap debris as small as 20 to 40 microns.

Silica Swimming Pool Filter Media

Silica Filter Media

MultiCyclone Pre-Filtration DeviceNEW!  Minimize Filter Maintenance.
Save water. Save time!

A MultiCyclone pre-filtration device can cut 80% of the dirt that clogs a cartridge filter reducing the number of times the cartridge needs to be cleaned as well as replaced.

Learn More

Pro™ Series Top-Mount Filters

Pro™ Series Top-Mount Filters

Providing you with quality you can trust, the Pro Series high-rate sand filters incorporate the latest pool filter technology to ensure your pool is operating at its very best. Moulded of durable, corrosion-proof reinforced thermoplastic, they feature attractive, unitized tank construction for years of trouble-free operation with only minimal care. Pro Series sets a new standard for performance, value and dependability.


  1. Flange Clamp Design allows 360° rotation of valve to simplify plumbing.
    • 7 Position Hayward Vari-Flo control valve with easy-to-use lever-action handle lets you dial any of the valve/filter functions.
    • Integral sight glass lets you see when backwash cycle is completed.
  2. Integral Top Diffuser ensures even distribution of water over the top of the sand media bed. Full-size internal piping gives a smooth, free-flowing performance.
Pro™ Series Top-Mount Filters: Features
  1. Unitized, Corrosion-Proof Filter Tank moulded of tough, durable colourfast reinforced thermoplastic for dependable, all-weather performance with only minimal care.
  2. Efficient, Multi-Lateral Underdrain Assembly with precision engineered, umbrella-fold, self-cleaning laterals for balanced flow and backwashing, plus easy serviceability.
  3. Integral Moulded Drain Plug for easy draining of tank, without the loss of sand.
  4. Totally Corrosion-Proof Base is rugged and attractively styled to provide strong, stable support.


  • Aboveground and Inground pools of all types and sizes
  • In-ground spas (residential or commercial)
  • Water features (fish ponds, fountains, water gardens)

Available Sizes

  • 18″
  • 21″
  • 22″
  • 24″
  • 31″ (Special Order Only)
  • 36″ (Special Order Only)


Performance Data for Pro Series Top Mount Filters
Performance Data for Pro Series Top Mount Filters

Typical Installation of Pro Series Top Mount Filters

Activate Dual Grade Filter Media

Kickin’ it old school with New Technology!

Introducing Dr. Dryden’s Activate Dual Grade Filter Media!

Activate was invented by Marine Biologist, Dr. Dryden. Activate is a permanent glass filter media designed to provide consumers with cleaner, healthier water. This activated permanent filter media, made from recycled glass, goes through a patented process of decontamination, sterilization, shaping and activation. The glass is non-porous and very hard; it will not physically break down, unlike sand.

Activate exceeds the performance of quartz and glass sand by filtering about 30% more organics, restraining the formation of biofilm. With lower running costs and better performance, less chlorine will be consumed while simultaneously reducing about 50% of disinfection by-products. Activate also sustainably controls heavy metals and metalloids, such as iron, arsenic and manganese. Activate is a lifetime media – no media change is necessary!

Activate permanent glass filter media

How does it work?

Due to negatively charged ions, Activate is more effective at attracting and capturing bacteria and algae, fundamentally preventing the formation of biofilm. As clean filtered water leaves the fine media, it picks up speed as it passes through the course media, ultimately increasing flow rate. The filter media itself has about 300 times more surface area than silica sand, making its filtration capabilities superior, resulting in clearer and healthier water.


ACTIVATE comes in two different grades – COARSE (Grade 2) and FINE (Grade 1). Use ACTIVATE COARSE on the bottom of the filter and ACTIVATE FINE as a top layer. Once ACTIVATE is installed, back-wash the filter 3 times prior to use.

Dr. Dryden’s ACTIVATE is provided in sealed bags ready for use. Follow the sand filter manufacturer’s instructions for filing the filter with sand and follow the steps below to determine the right amount of Dr. Dryden’s ACTIVATE for your filter.

Activate permanent glass filter media layering instructions

Amount of filter sand needed per manufacturer's instructionsNumber of bags needed of Dr. Dryden's ACTIVATE
100 lbs31
150 lbs41
200 lbs52
250 lbs72
300 lbs82
350 lbs93

The Dr. Dryden story:Dryden Aqua

When sea mammals like dolphins, whales, or sea lions are kept in captivity, it is often in chlorinated water. Dr. Dryden worked with these mammals in like conditions for many years. He noticed they often die of lung infections at a young age.

He was able to prove that lung infections in mammals is due to harmful air they are breathing that is just above the surface of the water. This harmful air is what we call trichloramine which is the primary cause of chlorine odour that we smell in swimming pools.

Dr. Dryden invented an activated filter media called Activate. Using Activate helped save the lives of dolphins and other mammals by drastically reducing the formation of harmful trichloramines in chlorinated systems.

AFM is a filter media manufactured from green container glass. The glass has been purified, heated to over 1000 deg C and then reduced in size to a very specific particle size and shape. The glass is then treated by a two stage chemical and third stage thermal process to produce an activated mesoporous surface which is 300 times greater area. The surface can adsorb organics such as chloramines and particles down to 1 micron.
AFM filters 97% of all particles in the water down to 5 microns at  a water flow of 20m/hr, sand achieves 72% so in terms of what is left in the water, 3% for AFM and 28% for sand,  AFM is almost 10 times better than sand. The mechanical filtration performance of zeolite and all crushed glass products tested by independent analysis confirms that AFM is best, followed by a good quality silica sand.
Yes because there is an improvement in filtration,  the chlorine oxidation demand of the water will be reduced by 50% to 90%.
AFM should be back-washed on a weekly basis for a minimum time frame of 3 minutes.
AFM will last for the life of the filtration system, technically it never needs to be replaced. Sand deteriorates with time.
AFM will usually double the clarity of the water. Turbidity is caused by dead bacteria and bits of bacterial cell biomass. Dead bacteria are almost as dangerous as living bacteria. AFM when used properly will reduce turbidity to under 0.05NTU which is equivalent to more than 25meters of clear visibility through the water. If you have essentially zero turbidity then you also remove cryptosporidium oocysts that are the main reason for disease out-breaks from pools.