Marineland Rite-size Ready-to-use Cartridge For Penguin 160/170 & 300/330

I like this for my smaller tank because they can be cleaned and used again. I only resuse the about three times then go ahead and replace it. Works well.

Pros: can be used again

Cons: none

These are easy to change but if you have alot of waste going through the filter i wouldn't leave them in too long. If you wait till there clogged to change then they will be completly clogged and quite gross when you pull it out. But if you do regular maintenance you can rinse it off and put it back. But this can only be done once then it's time for a new one.

Pros: Traps all the yuck that goes through the filter

Cons: messy and slimy to change