Koller ProductsSize Small Replacement Filter Cartridges - 3 Pack

The media could not be loaded.  I love using these. I ended up ordering the one with 6 in it after these. Same brand and same kind. These are the only refill cartridges I use now! I highly recommend buying these. They keep the water clear very well. After they do their job they are green from algae and fish feces. I do a 85-90% water change weekly, then change the replacement filter cartridges once a month. My tank stays pretty clean. It doesn’t take much to clean it since I started using these. Just a quick wipe inside the tank and the filter cartridge does the rest of the work for you! Easy to switch out for a new one.

These work great for my filter and last me about a month with four fish in my tank. True to size and inexpensive! Filter out my tank nicely.

Small bio-filter fit my water pump perfectly

It's pretty good. For my fish tank it is a bit long. Other than that it is easy to use and pretty easy to clean.

Used to be reasonably priced, now it's ridiculous!

Doesn’t it’s job

I’ve been using this filter replacement for my aquarium, I wish they could last longer. I have to change them every week, the filtration is not that great. You have clear water on the first couple days then the water gets cloudy and dirty. I thought I was doing something wrong while cleaning the aquarium but I realized after a while that the replacement filter doesn’t last.

Perfect size. Quality is good. Easy to use. Cleans my fish tank. Good material.

Es un producto muy bueno ya los he pedido varias veces