I am currently running a Tom Rapids RP3 filter on my 75 gallon saltwater aquarium. For those who aren't sure what this is, its kind of a mix between a canister and a wet dry trickle filter with a built in protein skimmer and auto top off. The stages of filtration that it came with are 1st: filter floss and carbon pad, 2nd: bioballs, 3rd: carbon pillow and ceramic/glass rings. I'm sure that there is better media to run in this filter but I'm not exactly sure what to replace and what to replace it with. My thoughts are to replace the 3rd stage with live rock rubble. Any thoughts on this? What could I replace the bioballs with? Any help would be greatly appreciated. I currently only have live rock/sand and 1 fish in the tank with a cleaner crew but I will be adding more fish and coral in the future.