Aqua Clear AquaClear Foam Filter Inserts, 3 Pack – Replacement Mechanical and Biological Filter Media for 70 Gallon Tanks

This is the same sponge that you get with your filter, it will work the same way. It's cheaper than most local pet stores will have them available for (though at my LFS the full filter was cheaper to buy in store but the media (sponges, carbon, etc.) were much cheaper here on amazon. I love the filter and these sponges, the only thing I'd say is that the recommended replacement time is clearly designed to sell more of these. You can easily make one of these sponges last over a year just by taking the sponge out of the filter, squeezing the sponge out, and rinsing it (I recommend rinsing in old aquarium water after you've done a water change, not while it's in the tank so you don't add chlorine or chloramine from the tap). An added advantage of continuing to use the same sponge for a long time is that it will keep your beneficial bacteria alive and well in the sponge effectively letting these function as both biological and mechanical (but NOT chemical if you're into that) filtration!

Good, firm, very open cell foam, slice to size for various applications.

Keeps my fish tank clean

Use these with Emperor 400 filters. Unfortunately they are hard to find now or discontinued 😭

It can be better if a little bigger

It’s a foam filter insert. Good value

I always buy this brand since the filter in my fish tank is the same. They work very well and help clean the water and remove any dirt. It comes 3 in each package and the price is very good. It can last 3 months depending on the cleaning and maintenance you give to your fish tank.

This is a great filter! You can see on the picture that is does a great job at keeping gunk out of the water. It is easy to use and I have been washing mine and reusing it a couple of times before throwing it away.