Poly FilterPoly-Bio-Marine, Fish Aquarium Filter Media Pad, 3-Pack, 4” x 8” (3-(Pack))

I use them all the time in my filters after they turn brown I discard and replace them .Water does NOT have to pass through them just cut piece you want or you can even roll it them put in your filter however IMO like every media for 2 days prior let them soak in water because I have found over years media will change PH if not soaked prior for 1 or 2 days , I play it safe thus 2 days and even my most delicate shrimp thrive .

Hi have done reviews on this project many times. Discovered it early in my interest in keeping aquarium fish. They “ Adsorb” dissolved organics and various chemicals. Which mean unlike carbon when full, leaches everything back into the aquarium water. It is priced more than carbon. But again it doesn’t leach back into aquarium water and lasts a very long time. And the color will change to let you know when it’s time to replace them. Wouldn’t use anything else to safeguard my fish

I use small sections of it in bags when transporting fish

I have used these for years. Easy way to help control phosphate and to polish water.

Great in taking organics out of your Aquarium. This item was first used in the medical field to filter out impurities from human blood in a dialysis machine. Does a great job in the home aquarium.

Really great! It brings down phosphates in a reef tank really well but you need to be careful because it brings it down too fast in a matter of hours. Could have a bad effect on sps coral. You can cut a smaller piece to have such a smaller effect. Go slow and monitor your phosphates and you'll be ok. Really does a great job on polishing the water too