I have 11 indian runners that have access to my 60,000L (13,000 gallon) pond and have experimented with numerous different designs for filtration but I have not yet found a solution that works without a good amount of manual maintenance. The most efficient I have come up with and using currently is a 3000L radial flow filter (aquaponic style settling tank) which then feeds into numerous 200L reed beds that have overflow catchment automatically overflowing into the next bed when they get blocked up. Once they block up (which is quite regularly) I have to pull the reeds out and wash them and the media. The muck goes on the garden which is fantastic for worms and soil health but it is quite a physical and heavy job to clean them out. You could use smaller reed beds to make it easier and lighter but they would just block up even quicker. I do need to change the design so the first reed bed being fed is always the oldest as at the moment they are all fed in a line so the first bed is clogged up much more often than the subsequent beds.
