REEF TANK BASICS
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THE TROPICAL CORAL REEF IS ONE OF THE MOST BEAUTIFUL AND DIVERSE ENVIRONMENTS ON OUR PLANET - IT IS A SMALL WONDER THAT MANY PEOPLE WILL TRY TO RECREATE A " PIECE"OF IT IN AN AQUARIUM. DEPENDING ON ONE'S APPROACH, THIS CAN EITHER BE A FASCINATING, EDUCATIONAL AND REWARDING EXPERIENCE OR A FRUSTRATING WASTE OF TIME, MONEY, AND NATURAL RESOURCES.
THE SET UP
Because the ocean is the most stable ecological systems on the earth, the creatures which live on the reef generally do not tolerate poor water quality. Excellent filtration is a must. This means a good quality protein skimmer ( a device which uses the oxygen in small air bubbles to remove certain organic wastes) and a high quality biological filter (such as a Big Al's Multi-Reef Trickle Filter, a.k.a. wet/dry or fluidized bed filter) (which uses oxygen - bacteria to reduce toxic ammonia to nitrate). These are essential pieces of equipment. Although it is possible to go smaller, in my opinion the minimum practical size would be 35 gallons, but a 50 to 60 gallons would be better. (The only exception being that if one has an exceptionally high-quality skimmer (such as the " Berlin" ) and is using lots of live rock, it may be possible to do away with a biological filter as the skimmer will remove many compounds which break down into ammonia, and live rock becomes a biological filter when set up properly (note that it is not as efficient as a trickle or fluidized bed filter).
Make certain that all equipment is sized correctly to the tank's capacity - over filtration is virtually impossible, under filtering is lethal. Light is critical, nearly all corals contain a tiny algae (called zooxanthellac) inside their bodies which gains shelter from microscopic predators and help eliminate the coral's waste and even helps feed it. Without proper light, the algae will die and so then will the coral. A good general rule of thumb is to provide 3 to 4 watts of light per gallon, varying with the height and surface area of the tank. If you think this is excessive, consider that the corals we keep are coming from shallow water in equatorial regions and you can perhaps imagine the intensity of light these animals receive in their natural environment. Full spectrum light with an emphasis on the ultraviolet end is required (in other words, not just any old bulb will do). For larger tanks, metal halide lights in combination with actinic fluorescent bulbs is the best, for smaller set ups, several types of fluorescent bulbs are on the market intended specifically for reef tanks. Note that if you are going fluorescent, you will need multiple fixtures to get anywhere close to adequate light. (Lights produce heat, especially halides; a ventilation fan is required if in a closed cabinet). The use of a glass or acrylic cover is not recommended as it filters out a substantial amout of UV light, furthermore, very tall tanks will also diffuse the passage of light.
Other equipment includes a heater, hydrometer ( a device which tells you how much salt is in the water), and several test kits: pH, Ammonia, Nitrite, and Nitrate are the most important, others such as Kh and phosphate can be purchased after a couple of months. As sea water consists of 52 different elements in precise ratios, a highquality Coralife synthetic salt mix is required (preferably one intended for reef aquaria), as well as a good quality (i.e. Big Al's Multi-purpose Water conditioner) dechlorinator/water conditioner. Unless you are using live sand, the use of a substrate is not recommended. An electrical grounder for aquarium use is also a wise investment, many fish and reef animals are highly sensitive to minute traces of electricity and salt water is highly conductive.
I cannot overstate the value of having a good book handy. (sort of like buying a new car without having an owners manual, insurance, and drivers license!). A good one for people thinking about setting up a salt tank (but not necessarily a reef) is the New Saltwater Handbook (Barron's) and the Manual of Marine Invertebrates (Tetra Press) is excellent resource for the reef keeper. An added bonus is that they are both written in " Plain English"- no Ph.D required!
After the tank has been set up and running for 24 to 48 hours, you are ready to cycle the tank (establish the nitrifying bacteria in your filters), a process which will take several weeks. The best way is to purchase live rock (collected in the ocean and full of various encrusting animals and micro organisms). You will need approximately 1 lb. / gallon, the majority of which should be base rock ( the cheapest form - having the least amount of growth). To maximize the filtering potential of the rock, use spray bars from your filter to encourage circulation and position the pieces to have lots of space around them, placing the largest on the bottom progressing to the smaller and nicer pieces on top. The product " Stress Zyme"should be added at the same time as the rock and once a week thereafter until the tank is conditioned. By testing the water 2 to 3 times per week, you will see the ammonia level rise and drop, followed by the nitrite level. ONLY when the nitrites have risen and then returned to 0 ppm, the tank is now ready for stocking.