In this video I talk about the role bacterias play in keeping a pond crystal clear and healthy. If you want to see some of the filters I've built for these ponds, have a scroll through this playlist- https://youtube.com/playlist?list=PLJ8Cv9jCFTGTGzqhdCKcWvNxjOyXH6DTy
You can also view some of the products I use on my ponds and the formulas I use to calculate flow rates, bog size, etc ,etc at https://ozponds.com/pond-equipment/