The Vortex Filter that I have installed on my koi pond is now more than 3 months old. I have since shut down other filter system and solely relying on the Vortex. The pond water remain clear with moderate feeding. Maintenance on the prefilter or settlement chamber is being done at 2 months interval that invoice flushing the brushes with pond water. There has not been any blockage so far and the result is good considering the fact that the filter is above ground with pond water feed to the filter via submersible pump.