Glass media lasts about 2-3 times as long as sand filter media. Sand will require longer backwashing to clean the dirt out of the system as there is more volume of media to go through. Glass media will backwash quicker as the material is lighter and less dense, so it floats better, resulting in faster cleaning.
When to change your filter media It is recommended to change your sand media every 5 years and glass media every 10 years. If you notice the water is cloudy or the back wash is not working correctly, the media needs to be change. However, you may have to replace the filter sooner depending on the filtration process.
Cartridge filters should have the filter element replaced around every 18-24 months.