Step 1
Make a saltwater solution. The salinity is up to you, but too much salt can cause erosion. The salinity of seawater is about 3.5%, or 35 parts salt per 1,000 parts water.
Step 2
Fill the reservoir of your fountain with the saltwater solution just as you would with freshwater. All fountains are different, so consult a manual to know exactly how to fill your fountain.
Step 3
Change the water in your fountain with some frequency. Even though saltwater keeps fountains cleaner than freshwater, you will still need to change the filters periodically. Change the water out with a new batch each time you clean the fountain.