Below are Entries for the Nitrogen contest: We decided to post all ---since there is only 4 If you haven't seen it here is a link to the rules http://www.3reef.com/forums/swc-ski...120-cone-simmer-sulphur-denitrator-83827.html Thanks to everybody who submitted and to those who vote! Entry by DboShibby The Nitrogen Cycle By DboShibby The nitrogen cycle in a reef aquarium is probably one of the most important things a hobbyist should know about before starting a aquarium. This cycle applies to all parts of fish keeping from full blown reef systems to goldfish. You must understand the steps of this cycle to be successful in the hobby. Do you ever wonder why someone has a new aquarium with nothing in it but rock? They are waiting for this cycle to be done to add livestock to the tank. The nitrogen cycle is based upon 4 different steps Ammonia -(NH3) enters our aquarium through decaying matter on new live rock and fish poop. Once the Cycle has started ammonia will rise. Bacteria on the rock will soon start to use ammonia as food and turn it into Nitrite. Ammonia is toxic to fish and will not be tolerated by most species. In a fully cycled tank ammonia should always measure zero. Nitrite- (NO2) This is the second bacteria that goes through the same cycle as ammonia. Nitrite is less toxic but is still not good in a aquarium and should also measure 0. Nitrite is then turned into Nitrate. Nitrate- (NO3) This bacteria is far less harmful to fish and invertebrates. Usually a lower level of Nitrate is present in a aquarium. Of course 0 is going to be better, but most species will be ok in the range from 0-20ppm (parts per million) Some aquariums have refugiums with certain macroalgea that feeds on nitrates. The algae is periodically thinned out to export some of the nutrients. The only way to rid your tank of Nitrates is through a water change, unless you have a working refugium. A water change will export some of the Nitrate and also add new trace elements to the water (in a reef aquarium) Nitrogen- This is the last part of the cycle. Nitrate turns into nitrogen which then releases into the air. On first setting up for tank the levels of these bacteria will rise and fall. Ammonia will rise, then Nitrite, and finally Nitrate. Once all levels are reading 0 the aquarium has finished its cycle. This can take up to 3-4 months to happen or if you get established live rock and sand it may never cycle. In order to start the cycle there has to be ammonia present in the system. In the old days people would put 1 or 2 hardy fish in the tank to start the cycle. I am against this method as you are putting fish into toxic conditions. New ways of doing this are to add a uncooked piece of raw shrimp and let it decay. this will release ammonia to start the cycle. As this is happening you should be measure levels of all 3 bacteria to see what is happening in your aquarium. Once your cycle is complete you should only add 1-2 fish. Slowly stocking the aquarium will provide time for your aquarium to keep up with the new bioload. You should wait 1-2 weeks in between adding fish to the system. Entry by slocal What’s with the Empty Tank? By Rick Helton for Elite Reef of Denver, CO Okay, you’ve got your new tank, skimmer, sump, stand, lights, heater, rock and sand. Ready for that big Hippo Tang now? Nope, not if you want it to be happy and healthy. There’s a whole step you’re missing besides just physically setting up the equipment. This involves you, but what it requires is often the most difficult of all, patience. What is this step and why is it the most difficult? It’s called the nitrogen cycle or more commonly known as ‘the cycle.’ If fish didn’t eat or poop, the hobby of aquarium keeping would be a lot easier. The reality is that EVERYTHING that goes in the tank must be dealt with and the fact is that filters alone just won’t cut it. You need help on a bacterial level. Here’s the lowdown. In the ocean, everything is there for a specific reason and your equipment tries to replicate what the ocean does. Your lights are the sun. Your heater is the ocean currents and equivalent to latitudinal location. Your protein skimmer is the waves that make the scummy foam on the beach that smells funky. You get the point. The nitrogen cycle is actually something that is not artificially created at all. It’s the exact same process the ocean uses and best of all, it’s free! OK, Show Me the Cycle! Leftover food, dead critters and poop all release ammonia in to the water as they start to decay. Ammonia is deadly to most fish except for the hardiest and that is still at very low levels. You don’t want to be stuck with one or two types of fish, do you? Here comes the nitrosomonas. They are a type of bacteria that just loves to feed on ammonia. Unfortunately, they turn the ammonia in to nitrites. Nitrites are just as useful to the fish as the ammonia. They aren't. Ah, what would a cycle we recommend be without something good right? Let me introduce you to nitrobacter bacteria. As you’ve probably guessed, it feeds on the nitrates left behind by the nitrosomonas. The byproduct of this type of bacteria is the acceptable nitrate. Nitrate in low to moderate levels is tolerated by many marine fish. As you test your tank in the beginning stages, you should first see a spike in ammonia. That ammonia level will start to go down with the appearance of nitrites. Once you see nitrates start to rise and nitrites start to fall, you know you’re almost done with the nitrogen cycle process. Once ammonia and nitrites are at zero and nitrates are at least below twenty parts per million, you're ready to start stocking your tank. Each new addition will create a mini cycle so be sure to add fish slowly and one at a time so the tank can stabilize. Great, the cycle, but what if nitrates get too high? That’s where regular water changes and macro algae come in to play. Not only will a portion of your water keep nitrates at tolerable levels, but it also replenishes elements like magnesium and calcium that are absorbed by corals and coralline algae. How Do I Start this Cycle? Well, there are two main fields of thought on this. I will try to explain this as simply as possible. The first is to set up your tank and just toss a couple of raw shrimp in there and let them rot. Yes, really. As the shrimp rot, they release ammonia. The ammonia is turned in to nitrites and then the nitrites are turned in to nitrates. This method is definitely one way to make sure you get something rotting in the tank but many just don’t like the thought of an empty tank for weeks to possibly months. The second main method is to cycle with a live damsel or other hearty fish. Many don’t like this method as the water during the cycle is not even close to ideal conditions for a fish as well as the damsel isn’t quite known for getting along with other tank mates. On the other hand, you do have a neat little fishy to look at instead of an empty tank. Entry By Xmetalfan99 entry in .pdf form View attachment 25893d1267374643-nitrogen-cycle-contest-win-new-120-cone-simmer-sulphur-denitrator-nitrongen-cyc.pdf Entry By Siddique Why is this aquarium empty? Rocks and sand alone? Where are the fish?It’s undergoing a process known as a Nitrogen Cycle. The Nitrogen Cycle is defined as a biological process by which ammonia begins to form by dead or decaying matter brought into the aquarium from the rocks, sand, water, fish or fish food. The ammonia is broken down into nitrites and then broken down further into nitrates. When an aquarium is first set up, it is not considered “matured” enough to house fishes, corals or plants until it has undergone the nitrogen cycle. This process is usually considered the most difficult part of setting up an aquarium because the entire “cycle” process can take anywhere between two weeks to one month. Indeed, it requires a lot of patience that many of us lack. To be honest, it’s a bit boring to watch an empty, baron aquarium for this long. But, it’s by far the most important step in setting up your aquarium. WHY?It is considered the most important step because without completing this process, your fish, corals and plants are likely to perish because of the rise in ammonia which spikes during the first week of set up. Then, the Nitrosomas Bacteria begin to feed on the Ammonia, breaking it down into Nitrite between weeks two and three of the initial set up. Then, the Nitrites are broken down by beneficial Nitrifying Bacteria (Nitrobactor Bacteria) into Nitrates. These nitrates become near to zero or undectable by week four of the set up. The diagrams below illustrate this process. The only sure way to keep track of the “cycle” is to do frequent water testing. When the nitrates are zero, then and only then it is acceptable to begin stocking your aquarium. It is also very important to know your stocking limits and boundaries in order to establish and maintain a healthy environment for your fish, corals and plants.