Salt Method

• 1). Add 2/3 cup salt for each gallon of water in your tank. For example, if your tank holds 30 gallons, you'll need 20 cups of salt.
  
  
• 2). Swish the salt around, checking to ensure it completely dissolves.
  
  
• 3). Allow the tank to sit with the saltwater solution for a minimum of 30 minutes. If you don't need to reuse the aquarium right away, let the solution work for two to three days for best results.
  
  
• 4). Rinse the aquarium thoroughly with clean fresh water.
  
  

Bleach Method

• 1). Add bleach to the aquarium in a 20-to-1 ratio of water to bleach. For example, if your aquarium holds 20 gallons, add 1 gallon of bleach to the 20 gallons of water.
  
  
• 2). Turn on your filtration system, and allow the tank to filter this bleach solution for 24 to 48 hours.
  
  
• 3). Rinse the aquarium thoroughly with clean fresh water.
  
  
• 4). Add a dechlorinator to the tank before reintroducing fish. The required amount will vary depending on the product; read the instructions on your product's label. Dechlorinators work quickly, so you can reintroduce fish into the tank after waiting two to five minutes.