A: Great question. The main difference is power and lifespan: The RJ models are going to give you significantly more power and longer lifespan for the money.

Some other basic things that set them apart once they are:

The SJ models are very simple, easy-to-use systems. They have status lights that verify the unit is working, tell you at what power level it is set, and whether you need to clean the cell or add salt to the pool. This model also allows you to remove the cell plates and clean them with its included cleaning tool (no acid is required).

The RJ models are higher end systems that measure independently the pool's salt level, the water temperature, and the electronic performance levels of the cell so you can see exactly how things are working. The power levels on the RJ models can be turned up and down in smaller increments. RJ models also synchronize more easily with variable-speed pumps if you plan to upgrade. Answer provided by:  Administrator (4/8/2019)