Nova systems. Water filter and water softener. Filter contains 3 large separate filters (2 for sediment and 1 for organics/chlorine which is activated carbon). They probably should be changed once a year if you are full time or home is occupied year round (rented). You will need to add salt every couple of months. You can use sodium chloride or potassium chloride. Sodium is about $8-9 a bag and potassium is about $35 a bag. This is used to regenerate the softener and the flush water usually is piped through the garage wall. Then it runs either into a landscaped area or the yard. Sodium can & will kill grass and plants. Potassium will not harm plants. In fact it is a component of fertilizer.
Check out their website:
Nova Filters | Water Softeners | The Villages Fl
And when you get it installed, remove the filter in your refrigerator. It is no longer needed but will grow bacteria over time if left in place. When you remove the filter, you may need a bypass plug - depends on the refrigerator.