Dr. Howard Dryden is the founder of Dryden Aqua Ltd and a marine biologist from Edinburgh. The company was founded by his doctoral research on filtration systems with molecular sieve zeolite sand exchange for closed system aquaculture and the development of intensive aquaculture technology. Dr. Dryden has a unique combination of knowledge of biology, chemistry and technology and is the inventor of activated, biologically resistant AFM® filters. Dr. Dryden is one of the world 's leading experts on sustainable water treatment.

Dryden Aqua is one of the largest manufacturers of glass filters. As marine biologists, they have a unique combination of knowledge and detailed understanding of biological as well as physicochemical reactions in water. This allowed them to develop and manufacture a highly innovative product range such as Activated Filter Media AFM®. They provide sustainable and cost-effective solutions for the beverage and wastewater industry, for aquariums and aquatic life support systems, and for swimming pools worldwide.

The biological approach to pool water treatment

Bacteria and other pathogens in swimming pools cause many problems:

  • Risk of infections
  • Biofilm formation in the filter that reduces filtration efficiency and backwash
  • Toxic air conditions and chlorine odor
  • Increase in operating costs (washing, consumption of chemicals, exchange of filter media).

Traditional water treatment tries to solve this problem with high doses of chlorine, UV or ozone.

Dryden Aqua with the integrated Dryden DAISY ® pool water treatment system implements the biological approach, which prevents the growth of bacteria and pathogens and minimizes the need for chlorine and other disinfectants.

It is based on three principles:

  1. Without substrate: Sand is a natural breeding ground for bacteria. It replaces common sand with AFM ®, which is completely resistant to biopollution and therefore bacteria have no substrate on which to grow and multiply.
  2. Nutrients free: Mechanical filtration alone can not remove most of the nutrients for bacteria. The advanced compounding, flocculation and filtration process will remove the nutrients from the water so the bacteria can not grow.
  3. Lower chlorine demand: Dryden DAISY ® can filter all particles up to 0.1 micron reducing the demand for chlorine and the formation of harmful disinfection by-products to the lowest possible level.


AFM® Activated Filter Media is an instant sand replacement, doubling the performance of sand filters.

AFM® resists bioconnection, bioaggregation and transient infiltration of unfiltered wormhole and surpasses all other filter media.

AFM® is a highly engineered product made from a specific type of glass, processed to achieve optimal particle size and shape.

Photocatalyst & chlorine stabilizer ACO®

ACO® is an extremely innovative, environmentally friendly liquid product, highly effective in any outdoor pool, including seawater pools.

ACO® has two main features:

  • increases the natural disinfection power of the sun
  • free radicals are produced to enhance the oxidation of the sun.

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Multi-action coagulant and flocculant APF

It is a combined product that contains not only flocculation ingredients but also coagulation ingredients. It contains 5 active ingredients and therefore covers a wide range (Multi-spectrum). APF® in combination with AFM® and ZPM will achieve the best possible filtration performance. A Dryden DAISY system will remove all particles in the dimension of 0.1 m.

The best coagulant and flocculant

  • Removes as many particles and bacteria as possible from the water
  • Removes phosphates that are necessary for the growth of algae and bacteria
  • What is filtered does not need to be oxidized -> reduced chlorine consumption
  • Works perfectly with AFM®

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DA-GEN Generator

DA-GEN mainly produces free radicals for water disinfection - fast and without toxic by-products.

For residual disinfection we produce a very small amount of chlorine.

DA-GEN is also a complete pool controller.

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