Difficulty: Moderately Easy
Things You’ll Need:
- Large, at least 3 gallon, grow pot or other container to hold your filter. It could be a dishpan or large rubber container.
- Pair of old pantyhose or other mesh bags
- * Ten or twenty or more pounds of lava rock, depending on your pond size. Lava rock is available at most any big box store or plant nurseries.
- •Submersible pond pump and tubing
Step1
Lava rocks are dusty and dirty. They have been sitting outside for months and need washing before you put them in your pond. Wash them using your garden hose. Do not wash the rocks except in the yard. If you wash them on a patio or in a driveway, you will have to clean the patio or the driveway afterwards.
Step2
Put the clean lava rocks in the mesh bags or panty hose legs. Do not put too many in one bag because they can get very heavy when full of water and fish waste. Make sure you can easily pick the rocks up out of the pond.
Step3
If your grow pot is old, wash it. Put the pump, with the tubing attached to it, in the grow pot or other container. Lay it on its side for better performance. Let the tubing, which will eventually go over your waterfall or connect to your fountain, stick out of the top of your container. Make sure the electrical cord is also sticking out the top of the container.
Step4
Put the bags of lava rock on top of your pump in your container.
Step5
Place the pot with the pump and the lava rocks in the water. Plug in the pump. The pump will suck the water through the lava rocks, out the tubing at the top and be a perfect biofilter.
Novice 
