Aqua Clear's last a loooong time. I have had the same 2 Aqua Clear 200's running for about 15 years. The flexibility of what you can do with them is great. If you want 2 foam blocks instead of 1, have at it. If you want a bag of charcoal and an anti-ammonia bag as well, you can.
They are like Burger King...Have it your way!