Welcome to the College of Filtration

Because this topic can easily get out of hand, we’re going to ask a couple of favors of you. First, let’s agree to keep our discussion as general and accessible as possible, even at the risk of oversimplifying. There will be plenty of time for more detailed discussions by more qualified Visiting Professors in the future.

Next, let’s begin with the shortest, most inclusive definition possible of “Filtration”, which for our purposes might be simply “the removal of unwanted substances”. This is obviously a very broad interpretation of the concept, but it allows us to include certain types of devices like Ultra Violet Sterilizers, Ozone Generators and Ionizers in this discussion, even though they are not ‘Filters’ in the traditional sense at all. We’ve been fielding a lot of questions about them and this is as good a place as any, so let’s agree to include them under the heading of Filters.

Last, there are many ways to organize the topic of filtration, all equally valid. In the interests of clarity and organization, we’ve decided to go with a functional approach. We’ll start with Filtration 101 - Mechanical Filtration, the removal of solid particles, including Prefilters like Pump Screens, Submersible Filters and Skimmers.

Then we’ll move on to Biological Filtration, which happens all the time, everywhere in the pond, but we’ll concentrate on the biological components of mechanical filters - Upflow, Downflow, In-Pond and Pressurized - in Filtration 201. In Filtration 301 – Natural Filtration, we’ll discuss how to harness Mother Nature’s way of keeping water clean and clear, with Bog Filtration and Phytofiltration. Finally, we’ll get into the UV’s and Ionizers we mentioned that can treat the water to remove unwanted algae, in Filtration 401 – The “Un-Filters”.