The salt can also damage and burn plants if the salt granules land directly on the plants or too close to them. Never, ever put salt granules directly into the biological filter, or dissolve the salt so that its highest concentration is immediately drawn into the filter. The rapid increase in salt concentration will shock the bacteria and easily kill them. Bacteria are not so affected by salt if the saline concentration is very low. Wind, Rain and Water Change Weather conditions such as wind and rain can quickly change how much salt there is in a pond or water feature.
Rain adds water to the pond and reduces the percentage of salt in the water.
Use one of the many kinds of test kits available for determining the salinity of the water. Then add more salt to the water to restore it to the proper saline level. Wind causes the pond water to evaporate, increasing the percentage of salt in the water. Again, the proper method is to test the salinity of the water, and then add more water until the proper saline level is reached. If you do a water change, you also change the amount of salt in the pond.