We are often asked this question, as users of our filters are often surprised by the filtration speed.

Firstly, flow rate is not necessarily an indication of effectiveness. A filter can be very slow and ineffective or fast and effective. The only rule is that the flow rate must be controlled by its design and be in line with its composition.

Most filters are designed with compressed, dense activated carbon in a resin. This is the case with Berkey filters. This gives them a fairly slow flow rate. However, this is not necessarily a guarantee of quality.

Ultimate Star Filter® filters are composite filters, unique in their design, using a very different and patented technology. The outer layer is a mixture of activated carbon, blended with other filtering components. This low-density layer is obtained through a specific manufacturing process. The inner layer is composed of a nanofiltration membrane. Together, this provides highly effective filtration (see the analyses for yourself, which are the only factual proof of a filter's real effectiveness), with a faster flow rate than conventional filters composed solely of high-density compressed carbon.

So don't worry about the filtration quality or the flow rate, which you may find fast at first.

As an example, here are the flow rates normally observed:

These flow rates may vary depending on the hardness of the water, the quality and frequency of maintenance, the source of the water (tap water or other), and the proper priming of your filters.