guy has filter pads...he said they work well. His are made for marine and fresh. He said they go right into the canister filter. We are contemplating using this method for a few weeks, to get the phospate out kill off the staghorn algae we have. We believe the culprit was food. The food doesn't even have time to hit the surface before it's eaten, but for a while we tried a new food they didn't take to...so I think it broke down in the water. We do regular water changes, gravel vacuuming, etc...and our municipal water is ok. So, it has to be the water. We don't have an overload of fish and every other water chemistry aspect of the tank is wonderful. So, we'll see how it works.