How to Kill Bacteria With Salt in an Aquarium

Adding salt to a freshwater aquarium does not make it a salt water tank, but small amounts of salt are beneficial to the fish and will kill bacteria. Most organisms naturally contain salt ions, with fish having higher concentrations than bacteria. If the surrounding water has a higher salinity than the organisms in it, a process known as osmotic pressure will leach fluids and salt from the organisms, dehydrating and killing them. The simple cell organisms that make up bacteria die in a tank containing small amounts of salt, but many fish will thrive in the same environment.

Things You'll Need

Salt containing no additives
Bucket

Instructions

- 1
  Buy salt. Table salt is acceptable to use in an aquarium, but read the ingredients and buy natural salt with no additives. You can find it in supermarkets in the natural food section. The salt used should only contain its natural ingredients, sodium and chloride.
- 2
  Add salt to the aquarium. Remove all live plants and dissolve the salt into a bucket of freshwater. The salt will cause the plants to wilt. When the salt is completely dissolved, slowly pour it into the tank. Use 1 teaspoon of salt per gallon of water. The filtering system will move it through the water and distribute it evenly. Slowly add the plants back to the aquarium after several days of filtering the water.
- 3
  Maintain salt levels to kill bacteria and keep fish healthy. Test kits and instruments sold that measure the salinity levels of saltwater or marine aquariums will not be able to detect the low levels of salt added to a freshwater tank. The salinity levels will be approximately 1.0005 to 1.0009 parts per thousand (ppt). Once salt is added it will not evaporate.
- 4
  Monitor water levels. If you make large water changes by removing 30 to 50 percent of the tank, add salt to accommodate the loss by calculating how many gallons of water are being added and add the appropriate amount of salt.