I have been using a vortex filter for my koi pond for quite a while and in recent time, the efficiency of water filtration of this vortex filter drop substantially as a result of poorer performance of my old Tsurumi Pump that feed water to the filter. I have since install a new Tsurumi Pump for the vortex and the new pump is much bigger than the older one and the flow rate is higher too. It surely move more than 2000 gallon of water per hour.
Good to know that after the installation process, the water flow rate is fast and yet there is no need for me to use a reducing valve to cut down the flow rate to prevent water overflowing out of the filter. The water settled down with the water level in the first settlement chamber of the first vortex at less than a inch from the cover of the vortex. This mean to say that I need to ensure that the settlement chamber of the first vortex is not clogged or else the water may have to rise to achieve a water head big enough to push the water to the 2nd chamber. This will cause water overflow and hence regular maintenance of the first chamber need to be done at a much closer interval.