Do Homemade Pond Filters Really Work?

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Written By Mark Washburn

Mark has 20 years of experience as a professional pond management consultant.

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One of the most popularly searched on pond topics today is for plans or designs on diy pond filters. Homemade pond filters offer a potential cost savings over commercially made filters but a question that many people wonder about is are they any good? Do they really work all that well?

The short answer to this question is that yes, in many cases, diy pond filter designs can and do work quite well. However there are some variables that really need to be explored in a bit more detail to get a clear picture of what may work best for your pond.

Commercial pond filters are offered in quite a few configurations. You’ll find these in the form of pressurized bead filters (most expensive) down to a very simple biological filter, and most anything in between. A popular trend today is the combination of a biofilter and a uv light all encased in one single unit. For very small ponds, mechanical filters that simply filter sediments out of the water are very common and inexpensive.

Homemade Pond Filters Use Biological Filtration

For the purposes of comparison it’s important to realize that when we talk about a homemade pond filter and the commercial one’s, we’re specifically talking about biological filters. Regardless of the manufacturer, meaning you or someone else, all of these filters use a form of beneficial bacteria, which is housed in various kinds of media (we’ll talk about this more in a moment) and it’s these good working bugs that do most of the clean up work.

When a person is comparing a diy pond filter such as the Skippy design, or something like a 55 gallon barrel filter, vs. a waterfall filter, or a box type filter, these are all very similar in the processes they use to clean the pond water. The container or shell of them may look quite a bit different but the processes inside are virtually the same.

Biological Pond Filters And Media

Upon looking in any typical biofilter you may or may not find several prefilters which are pads of various densities that will catch some of the larger pieces of debris that will flow through the pond. After this stage, you’ll then discover the water flowing into a biological chamber which holds some type of media material that provides a home to the beneficial bacteria. Good examples of this would be sponge like pads, plastic coiling strands, small tubes with ridges on them, among other things. All of these provide a place where bacteria can set up shop, build up, and be somewhat protected from the water flow.

Beneficial bacteria will naturally break down any organic elements in the water and it’s one of the most powerful, natural ways that a pond owner can keep a pond in better shape. A typical homemade filter will often fill up from the bottom of the chamber. At the very bottom is a settling basin or area for non-organic particles to drop into. Things like sand, small rocks, and non-decomposing debris ends up here while other material that can be broken down will eventually decompose with the help of the bacteria. As the water rises in the filter it’s pushed through the bio chamber area, filtered and cleaned, and then it exits somewhere near the top. It can flow directly back into the pond at this point.

Sounds a lot like a typical waterfall biofilter doesn’t it?

This is why we say that some very good homemade filters will do just as good a job as many commercial versions. There are many similarities between them. What’s most important for a biofilter to work well isn’t really the shape of the design but how it’s managed by the pond owner. For the best performance you ideally want the full gallon volume of the pond to pass through the filtration system about once per hour if possible. This flow rate can vary a bit of course but ideally you want quite a few passes through the filter in a 24 hour period.

Tips For The Best Pond Filter Performance

It’s important to always remember what the real power of a biofilter is, and that’s the bacteria that’s inside it. If this get’s depleted or low due to something like a random chemical treatment, or perhaps the pond has been shut down for awhile for repairs, then some degree of priming or adding bacteria in the water will be important to make sure you have a lively colony working within the biofilter. Adding bacteria to the water from time to time is always a good idea to make sure the bacterial density is in great shape.

Unlike a pressurized filter, most homemade pond filters don’t have any way to backwash or clean out the insides of the filter. However this may not be necessary or advised once everything is set up and running well. One mistake many new pond owners make is to keep cleaning out the entire biofilter on a weekly basis. The fact is, the system is designed to operate without much cleaning if the bacteria is doing it’s job. There is evidence that many of these filters could actually work continuously for several years of continuous use without cleaning. It’s important to remember though that it can take something like six to eight weeks for everything to build up to the point where the filter is functioning at full capacity. In the early weeks it’s critical to try to remain patient despite the fact that your water may be emerald green. Eventually, it will usually clear up on it’s own.

Comparing Costs Of Filters

DIY projects are obviously very popular simply because there is the perception that they may save a lot of money over simply purchasing something off the shelf. I use the word “perception” intentionally because there have been many occasions when a do-it-yourself effort ends up costing more money in the long run. Pond filters are no exception to this so it’s important to do your homework before you proceed with any project.

  1. Be sure to get a solid, proven pond filter plan in place.  (you’ll find many online)
  2. The plans should have a detailed list of parts and ideally sources for those as well.  Add up the costs and don’t just assume you will be saving money!
  3. Get a very clear idea of the filtration needs of your pond such as the full gallon volume and the potential fish loading that you may one day have to deal with.
  4. Find and use a good quality beneficial bacteria product that’s appropriate for the season and temperature.  Supplement with these as needed, such as following any shutdowns of the pond.
  5. Avoid routine cleaning of the filter (and particularly the biological chamber) and remain patient in the early weeks of setting a new filter up.

Commercial pond filter designs will likely continue to get more and more complicated and along with this, one would expect improved and more efficient performance.  Like everything else in the pond care industry, new technology will continue to advance the hobby forward.  Nevertheless, there are times when the tried, true, and simple systems will win out and be a great option for many people.  Creative minds are always coming up with great diy projects that work very well.  You can be assured that homemade pond filters are on that list and are providing some great results for many pond owners.

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