re: #325 goddamnedfrank

A friend of mine has a 100gallon show tank modified for a Red Slider turtle. The ancient Marineland cartridge filter finally gave it up and I bought the modern equivalent. I love the trays for media, the volume of the water flow. But not at all sure how applicable the extra media is for fresh water. Ceramic cylinders? Plastic balls? Saltwater stuff, or am i just out of date on the art?