Sand vs. Defender

We are frequently asked to compare the features, functions and benefits of the Defender^® filter to the highly popular high rate sand filter. The differences fall into several categories including design, installation, operation and performance. The examples set forth in this website will compare a typical 2000 GPM recirculation rate

The basic difference between the Defender^® filter and conventional high-rate sand filters is the operating premise. Sand filters function utilizing depth filtration while the Defender^® functions with surface filtration.

Comparatively, the Defender^® filter incorporates about 10 times (10X) the filter area of a similarly sized sand filter and the particles removed from the water are retained on the surface of many fabric covered flex tubes.

The sand filter traps the same dirt particles deep in the media bed until backwashing is required. The process of lifting or fluidizing the bed takes time and in some cases, tens of thousands of gallons to backwash out the collected particles. With the Defender^® filter, simply emptying the vessel releases the particles collected during the filter cycle.

The Defender^® filter will save approximately 90-95% of waste water associated with sand filter backwashing. Backwashing time for a sand filter may range from 4-6 minutes- with a frequency requirement of twice a week. Defender^® Filter cleaning and maintenance requires a monthly media dump. The exact intervals are bather-load dependent. Media dumping discharges a quantity equivalent of two tank volumes.