When I tore out my old waterfall, I found I would also need to redo my filter system. I had never
liked the the "milk crate-blue furnace filter-lava rock filter." Don't get me wrong, this type of
filter works great, I just don't like it's look. What I need in my pond is an efficient pre-filter. The
water is circulated from it into my larger out of pond bio-filter, into the waterfall and back to the
pond. As I considered my pre-filter needs I remembered the principle of "KISS"--keep it simple
stupid. Below you will find the instructions for what is the simplest, effective filter I have tried.
The fact that it is cheap is the icing on the cake.
My pond is about 330 gallons you will need to adjust the size to correspond with your pond size.
Supplies:
These supplies can be purchased in one trip to your local home improvement super store.
- One 3 gallon rectangular Rubbermaid storage box with lid.
- blue furnace filter (enough to fill the storage container when cut to size-five feet worked for
me.)
Tools:
- Drill with a 1/4" bit
- Razor knife
- Scissors
Directions:
- Drill holes in sides and top of container. These should be about 2" apart.
- Using razor knife cut a hole in one side of container large enough for the pump cord and hose
to pass through.
- Using scissors cut the furnace filter to fit. One piece on the bottom, and pieces to fit around
the sides.
- Place pump inside the container and run the hose and cord out the side.
- Cut more furnace filter to cover the pump and fill up the filter about one inch above the top.
- Put the lid on.
- Sink the filter. It is light so you will need to hold it under until it fills with water.
- Plug in the pump and let it go to work!
How easy is that? The one I built cleared my little water garden in 24 hours. I have had to clean it
once this spring, I just replaced the furnace filter. The nice thing about cleaning this little guy is
you don't rupture a disk trying to pull it out of the water. I also think it looks much better in the
pond. You can even set baskets of plants on it to hide the whole thing.
Let me emphasize this is a prefilter, I don't worry if it has a bacteria colony or not, when the filter
medium clogs I just replace it. If you have a large pond, the more traditional lava rock filter may
be a better selection, but for a small pond this one works great.