This page describes my latest salt water reef tank setup. Visit my lessons learned page for a discussion on some of the things I've tried in previous setups which I've changed in this one.
I have a 100 gallon acrylic tank with standard dimensions (60"W x 16"D x 18"H). This rests on a custom cherry and birch cabinet which is built around a custom fabricated acrylic sump. A matching birch and cherry light hood houses VHO florescent lights.
The aquarium has a built in skimmer/sump drain in the back left corner. This is a 5" square box with slots cut out near the water surface that allows the surface water to flow in and down to the sump. A PVC pipe goes through a bulkhead mounted in the bottom of this square box to allow water to flow into the sump. This pipe has 3/16" holes drilled around the pipe approximately 3/4" from the top of the pipe. A few 1/8" holes are drilled in the pipe at lower levels. This arrangement significantly reduces the gurgling noise that typically occurs with these systems.
The pipe flows into a large sump built into the aquarium stand. The first stage of the sump provides a mechanical filter using easily replaceable filter floss material. A submersible Rio 2500 power head pumps water out of the sump back into the aquarium at the other end from the skimmer.
A second Rio 2500 supplies water to a Red Sea Berlin protein skimmer. The protein skimmer sits right inside the sump so there is no external plumbing required and the pump noise is absorbed by the water. The output of the protein skimmer flows back through the mechanical filter which eliminates all the microbubbles and improves filtration.
Currently, I have one additional power head (a RIO 1700) inside the aquarium to increase the currents in the tank. The number and size of in tank power heads should be determined by the kind of corals you want to have - some corals prefer a lot more current than others. I'd recommend putting sponge filters on the powerheads in the tank to protect against anything getting sucked into the inlet. Powerhead internal workings and anemones don't mix very well, for example.
I use an IceCap 660 ballast with four VHO florescent bulbs (two actinics). This provides enough light for virtually any of the corals I'd want to keep in my tank (although some need to be near the top of the tank). The only other alternative to VHOs for reef tanks is metal halide. These generate more light, but they require a significantly taller hood (which isn't very attractive in my opinion) and they generate significantly more heat.
I use a timer to turn the lights on and off. I have them turn on around 11:00 AM and off around 9:30 PM.
I do not use a wet/dry filter or any other active biological filter system to remove waste products. Instead, the aquarium is set up using a method first described by Dr. Jean Jaubert at the University of Nice, France in 1991. A perforated bottom partition is laid down first (I use honeycomb florescent lighting screens cut to size to create a ~3/4" layer). This is covered with a fine nylon screening. A layer of live coral sand approximately ~1" is evenly spread across this screening. Another layer of screening is added on top, keeping the layer thickness constant and preventing marine animals from disturbing this layer. Finally, another layer of live sand is added on top.
The multiple layers result in both aerobic and anaerobic bacteria and algae growth which remain permanently stratified, and provide fully closed loop system. The details are described in "The Reef Aquarium" volume one, but the end result is a stable calcium level in the tank, crystal clear water (no yellowing), and very low ammonia, nitrate, and nitrite levels without requiring periodic water changes. In my previous tank, I never changed any water for 18 months (only replenished what had evaporated) and the ammonia and nitrite levels were both around 0.001 mg/l, and the nitrate level was around 0.02 mg/l; all excellent numbers.
I also use a lot of live rock. The holes in this rock provide another habitat for helpful nitrifying bacteria.
One big advantage of this system, assuming you start with live sand and live rock that has been "seasoned" at your local fish store, is that you don't have to "cycle" the tank. It is ready for occupancy almost immediately after setting it up since the sand and rock already contain the beneficial bacteria.
Live rock adds significantly to the natural look of a reef tank. The use of the term "live rock" refers to the numerous living organisms that live in and on the rock. Any rock (assuming that it is clean and somewhat porous - volcanic rock is a good example) will become "live rock" over a period of time when placed in a healthy reef tank.
Live rock is normally shipped from the collector to your fish store wrapped in wet newspapers. Many of the organisms that were living on the rock will die during this shipping, resulting in ammonia formation. When live rock first arrives, your fish store will "season" the rock by keeping it in salt water with good circulation for about four weeks. This will allow the beneficial organisms to rid the rock of any remaining poisons (ammonia and nitrates) from the stressful trip to the fish store.
You can purchase "unseasoned" live rock for less than seasoned rock, and then do this seasoning yourself if you want. Make sure that you don't add unseasoned rock to an established reef tank since the significant increase in ammonia and nitrate levels could be deadly to your organisms. In fact, many books and fish stores recommend that you slowly add rock to your tank to avoid the possibility of adding too much unseasoned rock to your tank at one time. I've found that if you buy your rock from a reputable fish store and it's been seasoned it for at least four weeks, you shouldn't have a problem starting your tank with enough rock to fill the tank. I would then recommend checking the ammonia and nitrate levels 24 and 48 hours later to make sure that they are still low.
Maintaining temperature can be a little tricky, particularly if you live in an area with temperature extremes and you don't have air conditioning. Keeping the water warm enough is usually very easy since the heat added from the lights and pumps will usually be enough if the ambient temperature in the room is comfortable for humans. If you have the tank in a room where the heat is turned down at night, I'd recommend a thermostatically controlled heater. If you have one of these however, you should make sure you have a thermometer with an alarm (this is a good idea no matter what). I had the thermostat go out on one of these heaters and the temperate in my tank went up to 90 degrees before I noticed it - my corals were not impressed.
Keeping the water cool enough can be a little more difficult. You can add a chiller, but frankly this is more expensive than a room air conditioner. As long as the ambient temperature doesn't get too hot, you may be able to get away with evaporative cooling - just don't completely cover the tank. Of course, you'll have to add water to the tank more often if you do this.