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Bead Filter Media

AST Filter Media

Standard Bead Media performs biological and mechanical filtration and never needs replacing. These specially sized media are made of low density polyethylene, a plastic commonly used in food packaging. These beads float in the top of the filter, allowing water to pass through with minimal head loss, while trapping solids. The plastic media provides an attachment area for nitrifying bacteria to break down toxic fish wastes, ammonia and nitrite.

Standard Filter Media provides:

+ Excellent Biological Filtration

+ Superior Solids Removal

+ Low Head Loss

+ Superior Solids Capture

+ Low Water Loss (1-10% that of sand filters)

+ Never Needs Replacing

Enhanced Media provides all of the same great benefits plus:

+ Robust Biofiltration (50% boost over Standard Media)

+ Protects the Biofilm from Frequent Backwashing

Enhanced media is shaped to protect the bio-film from abrasive backwashing. This makes it suitable for systems requiring frequent backwashing that have high biofiltration requirements, eliminating the need for moving bed bioreactors in many applications.

Standard Bead Media

Enhanced Bead Media

MBBR Curler Media


Clarification is the process of removing solids from water. Suspended solids in an aquatic system are generally small particles <100 microns of undigested or partially digested food, bacteria, algae, clay and silt suspended in the water column.  Fine suspended solids case gill irritation and reduce the clarity of the water, whereas large organic particles create a serious waste load problem by consuming tremendous amounts of oxygen, adversely effecting the water quality.  Bead filters remove suspended solids by at least four different mechanisms as water is passed through the packed bed of beads. Particles >100 microns are subjected to physical straining. For slightly smaller particles(50-100 microns) the dominant mechanism is settling. Suspended particles (5-50 microns) are removed by interception, a subtle process caused by collisions between the particle and the bead media surface. Finer particles (<20 microns) are removed through bioabsorption, the capture of particles by the bacteria biofilm. Bead filters are excellent clarification units, capable of maintaining display quality water at high waste loading rates. Studies have shown that AST bead filters capture 100% of particles >50 microns and 48% of particles in the 5-10 micron range per pass.

Better Than Sand

Bead Filters were originally invented to overcome some of the major problems with using sand filters. Compared to sand filters, bead filters are immune to biofouling, never requiring replacement of the bead media. They also minimize water usage and reduce energy costs by lowering pump head requirements. Backwash water loss rates for Propeller Bead® Filters are as low as 10% and PolyGeyser® Bead Filters are as low as 1% of those experienced by typical sand filters.

MBBR Curler Media

Curler Advance X-1 is a revolutionary new Bio-Media for use in Moving Bed Bioreactors for water purification in recirculating aquaculture systems – developed by Inter Aqua Advance. See Brochure.

AST also offers media for use with Moving Bed Bio Reactors (MBBR). This media is not used in our filters, but as a post process with our High Flow Propeller Bead ® Filters for augmented biofiltration.

Large Active Surface Area

The open curler design makes these elements particularly advantageous as carrier elements for nitrification in biofilters. These media stand apart from traditional bio-elements in their open profile which provides optimal conditions for maintaining a thin active biofilm on the surface. It is important to bear in mind that it is the active surface area that counts. This is the area that in practice can be utilized for bacterial growth and dictates the performance. In this respect the Curler Advance X-1 is superior to other products.

Easy to Clean

Easy cleaning is a crucial aspect of maintaining optimal nitrification performance or active surface area. If inactive layers of old biofilm are not continuously exfoliated, the interstitial area can clog greatly reducing the active surface area resulting in decreased nitrification performance. The Curler Advance X-1 is designed to enhance the cleaning capability and hence provide optimal nitrification by facilitating easy maintenance of a thin healthy biofilm.

About Bead Filters

Bead filters capture solids, while simultaneously providing a large surface area (400 ft2 /ft3 ) for the attachment of nitrifying bacteria which remove dissolved nitrogenous wastes. Bead filters are bioclarifiers, performing both biofiltration and clarification in a single unit. Bead filters are  distinguished from other filters by the use of plastic floating granular filter media. Water from the aquatic system passes up through the floating bed of plastic beads.

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