A Biofall filter is built into the top of a waterfall. This is considered one of the best types of filters for medium to large ponds. It combines a large filter pad with a good amount of biological media. When properly installed this filter type is easy to maintain and nearly invisible. It needs to be installed at the same time as the waterfall since it is incorporated into it.
The biofall has to be installed into the top of the waterfall. If you are installing the waterfall from scratch refer to the Installation - Waterfalls and Streams link Steps 1 - 5) for the first part of the installation.
Dig out a hole to match the shape of the filter. If the waterfall is on flat ground you will not need to prepare the ground beforehand.
Place the biofall into the hole and check to make sure it is level. You may need to pull it back out several times to make small touches to the shape of the hole until it fits properly. You want the unit to be tilted slightly forward to help prevent water running down the front. The front should be 2 fingers lower than the back.
Attach the tubing to the plumbing parts that fit into the hole in the bottom.
Apply seam tape to the front and around the sides of the unit. Peel the back off the seam tape and press the liner firmly into place. Then carefully lower the biofall back into place.
After the biofall is in position re-verify that it is level. Backfill the gaps around it with sand. Do not use dirt. Dirt will settle over time.