That size pool is about 7000 gallons, so the Saltron Retro would work well. It has the advantage of requiring virtually no installation, it just hangs over the wall of your pool and plugs in to a standard 110v outlet. It is a great way to save on chemical costs for a couple seasons, but if you're looking for the most long term savings, take a look at systems which install in the pool plumbing and offer longer lifespans and warranties.