Pond keeping is a relaxing hobby. But perhaps you don't have the space to dig a large, decorative pond. Or, it may seem too expensive to replace pond liners every few years. Because of these concerns, the container pond trend was born. A container pond is any pond built from a self-contained, rigid structure. That may be a bathtub, a rain barrel or a large plastic tub. The biggest advantages container ponds have is that they are more easily moved and cared for than traditional, permanent ponds. You can reuse and recycle an old bathtub into a container pond.
Choose a location for the bathtub pond. If you intend on keeping fish in your pond, choose semi-shady location, since direct sunlight stimulates algae growth. Not only will algae crowd your pond plants, it will rob the water of nutrients that fish and plants need.
Measure the length, width, and depth of the bathtub. Dig the hole for the bathtub pond using these measurements. Hollow out an area underneath where the bathtub drain will be, so you can drain the pond the water.
Seal the bathtub overflow drain. Use a pond sealant designed for concrete ponds. Apply the sealant using gloves and a putty knife. Smooth the sealant over and allow it to dry for 72 hours. Continue to reapply and allow time for the sealant to dry, as needed, until you have a smooth coat of sealant covering the overflow drain.
Use a regular rubber stopper for the bottom of the bathtub. The best, most airtight rubber stoppers are flat and take advantage of water pressure to remain in place. It is important that your bathtub drain not be permanently sealed, because draining portions of pond water will become necessary as debris builds up in the bottom of the pond over time.
Place the bathtub into the hole you dug.
Fill the pond with water. If you plan on placing fish in the water within two weeks, run the water through a water purifier first or treat it with chlorine-removing tablets. The water must be chlorine-free as chlorine can sicken or kill your fish.
Install a pond pump. This is not as crucial with a small container pond as it is with deeper, more permanent ponds. A pond pump will, however, help to properly oxygenate and filter the water in your bathtub pond, making it a healthier environment for fish and plants.
Introduce fish and aquatic plants to the bathtub pond, if you choose.