How Do I Reduce Salinity in My Salt Water Tank?

Maintaining a saltwater aquarium can be a very difficult task and is not often recommended for beginners. There are many different observations that must be made daily and measurements that must be taken, one of which is the amount of salt in the water, or its salinity. Occasionally, this salt level may need to be reduced to properly accommodate fish, a necessary skill if you're ever planning on keeping a saltwater aquarium.

  1. Reducing the Salinity

    • Reducing the salinity of the water is simply a matter of diluting it with freshwater. To do this, take a small amount of water out of the aquarium and dump it down the sink. Next, replace the water you just removed from the aquarium with the same amount of freshwater. Remember that the freshwater should be dechlorinated beforehand, especially if you're adding water to a tank that already has fish. After each removal of saltwater and addition of freshwater, measure the salinity using a hydrometer until you've reached the desired amount.

    Hydrometers

    • Hydrometers are special tools used by saltwater aquarium keepers that measure the specific gravity of the tank's water, and in turn its salinity. To use a hydrometer, simply place it under the water's surface until it fills up, then take it out and place it a on a level surface. Inside you should see a small, plastic arrow pointing to the water's salinity. Ideally, most aquarium keepers aim for between 1.019 and 1.025 ppt on the hydrometer's scale, but this really depends on your fish, so make sure to consult an expert or do some research on your particular fish to find out which specific gravity they deserve.