Hello! We had a pond installed last year at this time and absolutely love it but the installer failed to set up any type of filter system and we spent more time trying to clean the pond than sitting by and enjoying it. Last month we set up an external biofilter and the pond is so much cleaner but now we are having problems with the waterfall. We have a 200020 Sunterra pump that goes directly to the biofilter. We installed a drain and PVC pipe that goes directly to the fall from the filter. We also put a 400 gallon per hour pump in the biofilter and connected a hose to go out the drain to try and increase the pressure but the fall is still slow. Anyone have ideas on what we can do? Thanks!!