Clack Filter-Ag® has many outstanding advantages over the
more common granular filter media used for suspended
solids reduction. Its fractured edges and irregular surface
provides a high surface area and complex flow path for efficient
removal of suspended matter through out the filter bed,
typically reducing suspended solids down to the 20-40
micron range.The larger particle size creates less pressure
loss through the filter and allows deeper sediment penetration
into the bed for higher sediment loading and longer filter
This large and irregular shape prevents the screening and
caking of sediment in the top several inches of the filter bed
as happens in the typical sand filter, thus preventing a rapid
build up of headloss and blinding problems. Filter-Ag’s light
weight means lower backwash rates and better bed expansion
to release trapped sediment and rinse the filter media
during the backwash cycle. This ideal combina-tion of particle
shape, size and density make it a good choice where
quality water filtration and water conservation are important.
Although not intended to be an iron reduction media, extensive
field experi-ence has shown Filter-Ag’s rough and
jagged surface to be very good at entrapping the fragile iron
flock that forms after dissolved iron has been oxidized. The
fragmented edges are apparently good flock collection
points for the precipitated iron. Typical oxida-tion methods
include aeration, ozonation and chlorination.
Substantial savings can be realized when designing a system
using Clack Filter-Ag. Its low pressure drop, high service flow
rates and high bed loadings combined with lower backwash
rates allow economy in equipment downsizing and reduced
pumping requirements. Its light apparent density also saves
on handling expense and shipping costs.
Filter-Ag can be applied to systems designed for either pressure
or gravity flow. Because of its unique density, Filter-Ag
can also be used in multi-media (graded density) filter
designs allowing a more flexible approach to difficult filtration
There is less pressure loss through a bed of Filter-Ag ® than
through most other filter media
Light weight requires lower back-wash rates than those
required for other filter media
High service rates result in lower equipment costs and a
savings in space
High sediment reduction capacity results in longer filter
runs, with a substantial savings in backwash water and
time out of service
Reduced shipping cost due to light weight/cu. ft.
Replacement of sand with Filter Ag in existing installations
may increase filter capacity 100% or more. Caution
should be taken upon start-up that the lightweight Filter-
Ag is not washed to drain.
Color: Light grey to near white
Bulk Density: 24-26 lbs./cu. ft.
Specific Gravity: 2.25 gm/cc
Mesh Size: 12 x 30
Effective Size: 0.67 mm
Uniform Coefficient: 1.8
Hardness: 6 (Mohs scale)
Conditions for Operation:
Water pH range: wide range
Maximum water temperature: 140°F/60°C
Bed depth: 24-36 in.
Freeboard: 50% of bed depth (min.)
Service flow rate: 5 gpm/sq. ft., although considerably
higher rates are often used
Backwash flow rate: 8-10 gpm/sq. ft.
Backwash bed expansion: 20-40% of bed depth
Upon installation allow bed to soak overnight before