Hello BatchCookBetty80.
Solyanka is naturally salty due to pickles, olives, and cured meats, which can intensify when frozen. To fix this before freezing, you can dilute the soup with a bit of unsalted beef broth or water, or add diced unsalted potatoes to absorb some of the excess sodium while simmering. Another great option is adding a splash of lemon juice to balance the saltiness. I hope this helps you save your meal!