Thinking continuously how to filter my pond with the goal of improving water quality I started to really look at what I have. I know I need at least 3 filters, mechanical, biological, and chemical in a closed circulating system.
First there is the leaf basket in the skimmer. This catches some large floating items in the pond like freshly fallen leaves. The holes in the basket do allow some larger 1/4 inch items to get sucked through to the pump. I will call this my first mechanical filter.
The next stop on the plumbing path is the leaf basket on the pump. Any leaves sucked into this via the bottom drain or small items from the skimmer are now collected in this basket which has holes smaller than 1/8th inch. Mechanical filter # 2.
On the discharge side of my pump is my waterco multicyclone prefilter. This separates some of the finer particles that pass through it. So we’ll label this mechanical filter #3.
The water leaves the prefilter and goes to my main filter or my mini pressurized filter (to the jets). Both of these filters have areas for large particle collection areas as well as areas where biological nitrification can occur (mechanical + bio filters #4a and #4b). The large filter has a 5 inch chamber in the bottom where water can circulate before it flows upwards to the filter mats. The pressure filter has the usual pads.
From the large chamber water flows into the Veggie Filter (#5) which also seems to act as a settlement chamber for any particles that slip through the first 4 filters. The hyacinth roots are very fibrous and can trap dirt moving through it. The plants use up some of the nitrites and nitrates which in effect is chemical filtration.
Water then flows over my falls which has a layer of string algae which can also act as a filter using up the nitrogen before water returns to the main pond (Assuming I have not killed it with Algaefix). We’ll call this a weak bio/chemical filter #6.
But all along the path of plumbing and pond walls is a film of bacteria which will help transform the ammonia into nitrites. Rocks and other items in the pond and accessories also provide a hangout for bacteria so we will count these too. Bio film surface filters = #7.
The koi clay I add to the water supposedly absorbs and removes harmful chemical residues so we’ll consider it as a small chemical filter #7a. I have yet to see the miracle of clay in preventing algae but have only been using it for a couple of weeks.
So there it is, my pond has at least 7 filters. How many does yours have? Where along the path of your pond circulation system can you/I add the most filtration for the least cost?