Poly Filter Poly-Bio-Marine for Fish Aquarium - Works for Freshwater and Saltwater Fish Tanks - Filter Aquarium Media Pads - 3-Pack of 4in x 8in Pads

This stuff is a must have in any aquarium. I keep it in a 10 gallon quarantine tank to make sure there are no impurities as I am transitioning new fish.

Works very well and keeps aquariums so clean

I used this product when I had my first reef aquarium 30 years ago, and Im using it again now since I got back into the hobby. A lot has changed but PolyFilter is still around, that longevity says something. Mostly, it removes excess organics from my system, and I replace it every 3 weeks or so. Before I first started using PF on this new system, I checked my water for metal contaminants by Triton Labs testing. I had some excess tin (traced to some prematurely rusting pump screws), and it appears that PF subsequently removed that as well. It will remove quite a few contaminant metals, such as copper, lead, etc, but not all; for example, it will not remove lithium. Seems to have no effect on desirable cations like calcium, magnesium, potassium, or strontium.

Does exactly what claims to do. Great product

The best

Have been using these for about seven months and I cant believe how clear my fish tank water is. The filters turn a dark brown after a couple of weeks so I can only imagine what my water was like before using this filter. A bit pricey though.

Amazing

This really helps keep your tank clean effortlessly. Could not recommend enough!

These pads act as a mechanical filter and as a chemical filter. They keep the water pure and clean. Color changes to reveal what is being removed from the aquarium.

They are one of three stages of filtering and polishing water. Do a great job