How often should I change the cartridge in my shower filter?

[Polinvagen84]

Good day all! Guys, tell me how often you need to change the cartridge in the shower filter? I know that the cartridge is designed for 13,000 to 15,000 gallons of water. But the problem is that I don't know how to properly calculate the water! I bought this shower filter. I hope you can help! Thanks in advance.

[mich]

You might not be able to find the help you desire asking this question here.

Maybe you can try "Ask a question" on the company website.