I don't know. I bought the house with the pool and am unsure of when the previous owner changed out the media. Alternative media were looked at but pool sand won out just because I didn't want any other variables added to the equation. Supposedly sand is good for 5 years and it's relatively cheap and easy to find at home improvement shops.It is odd to me that my filter doesn’t seem to be collecting more, but it is brand new this summer. Has glass bead media. I haven’t researched filters much yet, but was told that’s an upgrade?