Live Rock vs. Wet/Dry: A Personal Look By PHAnemone Everywhere you look -- message boards, chat rooms or Internet Newsgroups -- a battle is being waged. Which is a better biofiltration system, Wet/Dry or Live Rock? Most pet stores will sell you a Wet/Dry system without ever mentioning Live Rock, and many longtime hobbyists swear by their bioballs.
All of this is just background to my own experience. In June of 1994, I set up my first reef tank. I purchased (or was sold) a SeaClear System II 65 gal. tank. This type of tank has a built-in Wet/Dry in the back of the tank. I filled the tank with 50 lbs. of Caribbean Live Rock, and 25 lbs. of tufa rock (another mistake, but that's another article). Throughout this time I made weekly eight-gallon water changes (using cured seawater), and hydrovacuumed the crushed coral substrate. By May 1995, my nitrates measured 140 ppm (and had measured that for over 6 months). I used a Dry Tab test kit to measure nitrates. Since my corals did not seem thrilled (actually, I was having trouble keeping any stoneys alive), I decided to attempt to correct my nitrate imbalance (I won't even mention the hair algae that I couldn't get rid of). By regularly rinsing the pre-filter to the Wet/Dry and reducing feedings from every other day to twice a week, I managed to get the nitrates to 60 ppm in two months. The nitrates hovered around 60 ppm until September 1995, when I began removing the bioballs from the Wet/Dry. I removed one-third of the bioballs every two weeks. After I completed removing the bioballs, my nitrates regularly measured in the 20-40 ppm range, with the tendency to be closer to 20 ppm (those test kit colors get difficult to differentiate).
Am I saying that Live Rock is the only way to have a successful tank? Not at all. There are many ways to have a successful marine aquarium. Wet/Dry systems (and fluidized sand beds) are very good at processing ammonia, and can be the system of choice in a heavily stocked fish only system. But for a reef tank, I'd say go with live rock. Other Resources AquariumHobbyist.com has a full line of species forums where you can discuss fish species with other owners, and hobbyists.
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The issue with newer hobbyists, and especially reef enthusiasts, is elevated nitrates in Wet/Dry systems. Wet/Dry systems create highly oxygenated water, which encourages the growth of the bacteria that transforms ammonia to nitrite, and nitrite to nitrate. The nitrate-consuming bacteria grow in a low-oxygen environment not found in a Wet/Dry system. This low-oxygen environment is found within the deep pores of Live Rock.
Are my nitrates still 20-40 ppm? Nope. I eventually turned the empty Wet/Dry area into a refugium, and added dry sand (with a few pounds of live) to my crushed coral substrate. Now I feed every day, don't hydrovacuum the substrate (although I still do the eight-gallon weekly water changes), and even with the additional feedings, my nitrates hover around 10 ppm. My belief that my water quality is much better now is primarily subjective (except for the nitrate reading). But, my tank has gone from a stoney killer to a home for an Anchor coral (Euphyllia ancora) that has doubled in size, a Long-Tentacled Plate coral (Heliofungia actiniformis) and a Purple-Tip Acropora. The main reason I don't have more stoney corals in my tank is because I had a Rose Bulb Anemone (Entacmaea quadricolor) that was surviving in my tank prior to my change to Live Rock (nine other anemones had died in this tank prior to this Rose Bulb). This anemone has since split into 10 anemones. Six of these anemones are still in the tank, and severely limit my ability to add any new corals. Additionally, now I actually have to feed my tangs and Mithrax crabs algae sheets, since there isn't any macroalgae growth in the tank. Other factors undoubtedly contributed to the success I've had. A lighting upgrade from NO flourescents to VHO jumps to mind. But even with this additional lighting, my problem algae growth diminished (actually disappeared), and water quality is always a key to any success (or failure) in this hobby.