Walmart offers the Intex Krystal Clear 15,000-Gallon Saltwater System, model no. 54601EG, for $139.99 with free shipping. That's the lowest total price we could find by $11, although we saw a similar model for $40 less last July. It filters chlorine to swimmer-save levels, purports to clean a maximum pool size of 15,000 gallons, and requires a filter pump with a flow rate between 700gph to 4,000gph.