Using a Cast Iron Tub as a Pond

• 1). Haul your tub to the desired location. Cast iron tubs can weigh in excess of 300 pounds, so enlist the help of some heavy equipment or at least a few friends. Bear in mind that once your tub is filled with water, it won't be moving any time soon. Choose a location that is a focal point in your garden, preferably out of direct sunlight (especially if you plan on adding fish or other livestock).
  
  
• 2). Install a pond pump to prevent the water from becoming stagnant. Some pump systems will work by running them through the existing drain hole, but if you have to drill additional openings, make sure to use a quality, grit-edged hole saw made of titanium or cobalt. Anything rated to cut steel will generally work fine on cast iron. Run your pump tubing according to manufacturer's instructions.
  
  
• 3). Patch any cracks, holes and spaces around pump plumbing with silicone.
  
  
• 4). Fill the tub slowly with water, and add any plants, rocks and décor.
  
  
• 5). Wait at least a week to add fish to your garden tub-pond, so that any chemicals in the water have a chance to dissipate and beneficial bacteria can begin to colonize.