A popular product in multiple industries and applications, the Bubble Bead Filter by AST offers easy maintenance and effective filtration. Perfect for aquaculture systems, research applications, quarantine systems, broodstock holding, and more.

Studies have shown that AST bead filters capture 100% of particles greater than 50 microns and 48% of particles in the 5-10 micron range per pass.

In addition to solids removal, these filters provide biological filtration, breaking down the nitrogenous wastes into non-toxic substances. Its gentle backwash removes the collected solids while keeping the necessary bio-film intact.


Product Features

  • Gentle Backwash: Does not harm the bio-film
  • Simple: Easy to understand and operate
  • Reliable: No internal moving parts
  • Energy Savings: Efficient design
  • Low Maintenance: Backwashing is quick
  • Longevity: Media never needs replacement
  • Superior Clarification: Removes solids effectively

Operation & Backwash

The Bubble Bead® Filter consists of 3 major zones –Filtration Bed, Washing Throat and Expansion Chamber. This filter is normally operated with 4 valves – the Inlet, Sludge, Air and Outlet.

During continuous filtration, water enters the filter at the bottom through a slotted inlet pipe, passes upward through the bead bed which floats in the upper filtration chamber, and exits through a slotted discharge pipe at the top.

During the backwash operation, the inlet can also serve as the sludge discharge if fitted with a 3-way valve. Air inflow at the washing throat provides a gentle air scrub of the media for trapped particle removal as the water drains from the filter. It contains no moving or mechanical parts for agitation of the bead bed.

Backwash operation includes 3 primary modes (diagram below): Filtration, Backwash, and Refilling. Backwashing is accomplished by completely draining all fluid from the unit. This causes the bead bed to collapse, and individual beads to be vigorously scrubbed by cavitation and bubbles as they are sucked downward through the washing throat. The backwashing process removes solids captured by the bead bed, but retains the beads with their delicate films of nitrifying bacteria.

  • Water is pumped through the Filter Inlet via a 3-way Valve positioned to (A).
  • Water passes upwards through Bead Bed for bioclarification and exits through outlet and a check valve back to aquatic system.

  • The pump is turned off and the 3-way Valve at the Inlet is turned to the Sludge Drain Position (B).
  • Backwashing is accomplished by completely draining the water from the filter.
  • As water drains from the filter, the check valve on the Efflient Line closes and air is sucked into the Air Inlet Check Valve.
  • Agitation of the beads is accomplished as air rises up through the Washing Throat and beads and water drop down into the Expansion Chamber.
  • As the beads enter the Expansion Chamber, they initially sink with momentum, and the float upwards as the water velocity decreases and bouyancy takes hold. As this occurs, water is sweeping past the beads which serves to carry away the solids freed from the bead media out of the filter.

  • Once the filter unit has drained completely, the 3-way Valve is returned to position (A) and the pump is turned back on.
  • Refill the filter, water and bead rises up to reform the bead bed.