The noticeable difference between a salt-water filter system and a standard chlorine-based pool is the amount of chemicals present in the water. Some above-ground pools can have as much as 10 parts per million (ppm) of chlorine in the pool at any given time. A salt-water system however, uses less chlorine and never has more than 1.0 ppm of chlorine in the water, while keeping it just as sanitized. Chlorine is more stable in a salt-water filter system and there's no need for algaecides either. Few chemicals are needed because the low chlorine levels do not affect the other aspects of water chemistry, such as alkalinity and pH.
In a salt-water system there is no need to use algaecide products. An algae cleaner does little for the disappearance of algae once it forms. It's used more as a preventive maintenance tool in chlorine-based pool systems; It's not used for salt-water systems. Therefore, if algae should bloom in your pool, shocking is the only reasonable course of action, not algaecides. One of the benefits of a salt-water system is that fewer chemicals are needed, including the use of algaecide which even in a chlorine system is optional.
Salt-water systems are designed with the idea that the filter may need to work harder to keep the water clean at some points during the season. Water is harder to sanitize in warmer temperatures and after excessive amounts of rainfall. In most cases you will never have to add shock to the pool, because the filter generates enough chlorine to continuously keep it clean. In the event you need to add shock, however, it will not affect your salt-water filter system.
You will need to shock the pool in rare occurrences after heavy rainfall, heavy swimmer usage or some other accident where debris falls into your pool and makes the water cloudy. Regardless of the filter system, shock is the first remedy to destroy an algae-filled swimming pool. Shock is used to quickly raise chlorine levels in your water in an effort to rid your pool of excessive germs, bacteria and algae before they become bigger problems.