Well I have 3 tanks, 180, 75, 29.
180- currently I have a Goldentail Moray Eel, Undulated Triggerfish, and Niger Triggerfish. I use a Wet/Dry filter with a Mag 1800 pump I also use activated carbon.
75-currently I have a Golden Puffer ($270 fish but my wife had to have it
), Lunare Wrasse, and yellowtail damsel. I also use a wet/dry filter with activated carbon.
29-currently I have a Blue Throat Triggerfish, Marine Betta, Percula Clownfish, Cowfish. All of these fish are very small and very shy. I use a hang on the back filter with activated carbon.