The motor in my pond’s all-in-one pump and filter burned up a few weeks ago, as motors are wont to do. Rather than spend $120 to replace the whole unit, I decided to install separate components this time around so I’ll be able to replace individual parts as they wear out.
After some online research, I decided I could make a biofilter a lot cheaper than I could buy one. Here’s what I came up with for our pond, which has a capacity somewhere around 50 gallons. A bigger pond obviously will require a bigger bucket and more pot scratchers and Scotch-Brite pads.
1-gallon tub with a lid (I used an empty ice-cream bucket)
10″ long PVC pipe, threaded at both ends (in plumber parlance, these are called “nipples”; you’ll want to take your pump along to the hardware store to make sure the nipple you buy is the correct diameter to fit)
12 plastic pot scratchers
6 Scotch-Brite pads
Pond or fountain pump
Hole-saw bit the same diameter as your PVC pipe
Good-sized drill bit (at least 1/4 inch)
Utility knife and/or sharp, heavy scissors
Start by preparing the bucket lid. Cut a hole in the center of the lid to accommodate the pipe, drill holes all over the lid, and cut a notch at the edge of the lid to accommodate the cord on the pump. (Note: The holes you see above are much too small. I used a 1/8-inch drill bit, thinking it would be sufficient, but the holes clogged quickly, dragging down the flow and putting unnecessary strain on the motor. The pump and filter functioned much better when I enlarged the holes to about 1/4 inch.)
Wrap one end of the nipple with Teflon tape and screw it into the pump.
Slide the free end of the nipple through the hole in the lid.
Set the pump in the center of the bucket and tuck the pot scratchers and Scotch-Brite pads around it. These materials will serve as a medium for growing the good bacteria your pond needs to break down organic material and keep the water clear.
Snap the lid onto the bucket, running the cord out through the notch you cut.
Set the pump in the bottom of your pond, holding it down if necessary for a minute or two to let it fill with water so it doesn’t float back up to the top. Plug in the pump and watch the clear water come out the top. (Note: You may need to adjust the flow rate on the pump to control the height of the spray.)
If you have a yard, and you don’t have a pond yet, I highly recommend building one next spring. Our bees love ours, as do the local toads, who bred out there all summer.