Bests & Worsts Reviews from Amazon

Couldn't find this at the local pet store and it was cheaper online. Works just like it should. A note to fish owners--you really shouldn't throw these out every few weeks like the packaging recommends, unless you're specifically using the carbon to get medication out of the water. Completely replacing these filters can actually be BAD for your aquarium because beneficial, toxin-removing organisms grow on the filters and naturally break down toxic fish waste into less harmful byproducts. If you get rid of these beneficial organisms by removing the filter media they inhabit, you can destroy the ability of your aquarium to naturally break down the deadly ammonia in your fish's waste. The carbon in the replacement filters is no substitute for a healthy bioload, and your aquarium's water chemistry can become unstable and dangerous to your fish, even with regular water changes. (Look up 'aquarium nitrogen cycle' for more info, or just look at all the reviews that talk about how their fish got sick or died after they replaced all their filters at once.) Instead, make a slit in the filter media, remove the carbon, and then rinse off the built-up gunk with NON-CHLORINATED water every few weeks (you can use the water you siphon out of your fish tank during water changes). You can use these filters until the actual filter media starts to wear thin and break down. Not only will you have a healthier aquarium, but you'll spend less on replacement filters!