If I did not originally purchase a salt system with my pool, can I convert it to salt later?

Yes. A salt system can always be added to an in ground pool. With some slight modifications to the equipment pad, the change is easily made. With an above ground pool, the change can be added later as long as the pool was originally categorized as salt friendly. These pools are normally completely or mostly resin with very minimum hardware. In both cases, adding a sacrificial anode to protect the metal components of the pool, is highly recommended ESPECIALLY if you have a pool heater. 

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