There are several different factors that can cause corrosion of above ground and in ground swimming pools. Some of these factors are keeping improper ph levels, total alkalinity, or even keeping improper salt or chlorine levels. It is very important to keep your swimming pool water chemistry at the proper levels, and also repair any swimming pool leaks.
Sacrificial anodes are used to help protect the metal components of your swimming pool when you are using a salt system. More information on this can be found here http://www.royalswimmingpools.com/yntech.pdf . There are several different types of sacrificial anodes. A utility anode can be placed in a skimmer basket, you will need to submerge it in the pool water and connect it to the metal part of your swimming pool you would like to protect. You may find the specifications on the utility anode here http://www.royalswimmingpools.com/utilityanodespecs.pdf
There are also anodes that are made specifically for your swimming pool ladder and you swimming pool light, to help prevent those items from becoming corroded.
Royal Swimming Pools also offers In-Line Anodes. In-Line anodes are constructed of a clear PVC, that makes for easy inspection. These anodes are designed for the protection of the metal components in your swimming pool heater. You can find the specifications for this anode here http://www.royalswimmingpools.com/inlineanodespecs.pdf
You can find the installation instructions for the anodes here http://www.royalswimmingpools.com/tninstall.pdf