So I set up a 100 gallon fish tank for salt water. I can't seem to figure out the difference in filtration for salt and fresh. Everything I read makes it sound like the only route is live rock. I have rock in my aquarium but its not live rock, will it become live once its been in there long enough? I also have a sponge filter and two hobs right now. I was wondering whats different about saltwater if its only a fowlr tank. What sorts of filtration should I avoid and which should I implement. I can't afford live rock, I live in FL and will be collecting the fish for the aquarium. Are sponge filters good, canister, hobs, or should I make a wet/dry? What type of media would I use, are spongies still effective?