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The nitrogen cycle is a natural cycle where beneficial bacteria breaks down toxic compounds into less toxic versions helping protect our livestock from their own waster. Each time one of these compounds is processed into another form (from ammonia to nitrites), they are made less toxic. The three compounds we see in aquariums are Ammonia, Nitrites and Nitrates. Ammonia which is generated by fish waste is far more toxic at only .25ppms, where nitrates (the end of the cycle) can get into the 200ppms before we see effects on our livestock. Understanding that ammonia is EXTREMELY toxic to livestock we NEVER recommend that you fish in prior to having this natural beneficial bacteria in our aquariums as it is cruel! In order to encourage these beneficial bacteria to grow, we need to start the cycle off with ammonia. After the tank has cycled for 4-8 weeks, this beneficial bacterial will help keep your fish safe from organic waste in your tank. We put together a little video you can watch to teach you how to quickly and painlessly cycle an aquarium.  

Cycling a tank is quite easy and often takes more patience than work. The start of this cycle is ammonia. Ammonia is introduced into the tank. We like Dr. Tim's Ammonium Chloride, but we can even use high organic aquasoils, like ADA Amazonia, that leach a lot of ammonia to cycle the tank. Some see aquasoils that leach of ammonia as a bad thing, but we see it as an easy way to start out your cycle so long as it leaches enough ammonia to get your aquarium water up to 2-3ppm.


How this works is the presence of ammonia causes natural beneficial bacteria to colonize. That bacteria' converts the ammonia into nitrites. Now with the presence of nitrites, another form of a natural beneficial bacteria ends up colonizing, breaking down the nitrites in nitrates, and that is the end of the cycle. However, there is no bacteria that breaks down nitrates thus forcing us to process water changes to remove them.

Nitrates, the end result of the nitrogen cycle, in low concentrations (5-15ppm) are actually a key nutrient to healthy plants. However, they are toxic to fish in high levels which is the main reason we need to process water changes.  Plants will actually uptake ammonia and nitrites, the more toxic compounds to fish, prior to up taking nitrates. Live plants act as a natural layer of protection for our fish.



If you're not able to watch our video on the cycling process, we'll walk you through the cycling process here.


When cycling a tank, all we need to do is add enough ammonia to have 2-3ppm in our aquarium's water. We should also not exceed 5ppm of ammonia. We suggest you use Dr. Tim's Ammonium Chloride as it makes adding ammonia very easy. Follow the directions on the back of the bottle by adding 4 drops per gallon of water to get to 2-3ppm.. and you have enough ammonia. See, its that easy. 


Now we wait 4-6 week. This is the hard part as everyone want to mess with the tank, and or process water changes. We just need to be patient and let the bacteria colonize. It is VERY important at this point that you have your filtration set up properly with dedicated biomedia like ceramic rings or something like Seachem Matrix. We don't need anything fancy, we just need a dedicated place for your bacteria to colonize and don't want to rely on our mechanical filtration, like sponges, to house the bacteria. We created a video you can watch below on how to set up filtration properly.

There are products that we can use to help speed the development of bacteria up, but we want to stress that they 100% NOT needed. You bacteria will develop all on its own if you give it time. However, if you are really impatient, you can use something we call "bacteria in a bottle". Not all bacteria in a bottle is created equal thought. There are some that are dormant, and some that are alive. The dormant bacterias like API Quick Start and Seachem Stability will help get bacteria going, but because they will not be as fast acting as live bacteria like Frtiz Turbo Start 700. Just know that additives like these are not needed, but can help speed the cycling process up.



 After about 4-6 weeks we need to test your aquarium water to make sure there is no more ammonia or nitrites, and everything has been processed out to nitrates. The easiest and more efficient way to do this is with API test kit. You can either buy API's Master Test Kit, or you can purchase a API Ammonia and/or Nitrite kit on their own. The big take away is that you should be zero ammonia and nitrites, and nitrates over 40ppm. If you don't see nitrates at 40ppm of above, then you didn't add enough ammonia and you need to add a little more. Also, if have a local fish store near you, a lot of the time they can test your water for you and let you know if your tank is cycled. Once the tank has confirmed that its been cycled, you should process a 100% water change to clean up the water column. 


There are a couple reasons in which your cycle can stall. One is that your PH is too low. If your PH drops below 6.0, this can delay or completly stall your cycling process. Even if you start with a lower PH, the cycling process causes an acidic byproduct which chips away at your KH, thus pulling on your PH. If you are having an issue with low PH, we recommend adding some backing soda (sodium bicarbonate) to your tank to bring your KH up, which will pull your PH up as well. Add 1/4 tsp for every 5 gallons of water to bring your KH up 4 degrees. 

Another reason your cycle can stall is by not having a dedicated area for your bacteria to develop. This is why we love canisters big and small. There is a dedicated area to add ceramic rings in which the bacteria can thrive. This is also why we don't like sponge filters. Yes they can develop lots of bacteria, but they are also part of your mechanical filtration. Mechanical filtration acts like a strainer in your aquarium water filtering out particulate matter and we need to rinse those out from time to time. But if when we have mechanical and biological filtration in one, we are essentially rinsing away your good bacteria along with the particulate matter than the filter strained out. We have seen too many people clean their sponge filters too well, thus killing off their beneficial bacteria racking havoc on their tanks. We refer to this as "crashing your cycle". As said earlier in this section, watch our video on how to set up your filtration properly and you'll never have an issue with crashing your cycle. 


Ok, so your tank is cycled and we know you want to add a ton of fish but you need to take it slow. We recommend that you only add one larger fish, or two medium sized fish, or a small school of fish at once. Understand that each time you add fish, your bacteria is going to need to grow to accommodate all the new fish waste.

Not it doesn't completely work like this, but a good analogy is 1 bacteria can cancel out 1 fish waste. When we cycle a tank the way we've outlined, we now have 2 bacteria which can cancel out 2 fish. So we go to the store and get 2 medium sized fish and add them to the tank. But a week later we want to add 2 more fish giving us a total of 4 fish, and we need to give the tank time to develop 4 a total of 4 bacteria which it will do naturally. We definetly don't want to go adding 10 fish, when we only have 2 bacteria in the tank, if that makes sense. Just take things slow and spread out the addition of fish. Your pocket book and significate other will appreicate it ;) 


So you've maybe noticed some algae, or your fish are acting weird and you test your ammonia and BAM, you're at 2ppms. AAAHHHHH! No need to freak out. We need to so two things. 1) Find out why we have ammonia again... and 2) Process larger water changes to bring our ammonia back down. Below are a few reasons why we could be showing ammonia: 


  • ISSUE: You have ammonia in the water source you are using for water changes.

    • RESOLUTION: We'd suggest running a RODI filter to remove all of your water impurities and bypass dealing with the ammonia altogether. Using water with ammonia in it is one of the toughest things to deal with when keeping aquascapes. You can run ammonia removing chemical filtration on the tank alongside with dosing Seachem Prime's emergency dosage, but then we are doing a lot to sidestep the issues, instead of just removing the ammonia altogether with a RODI unit. Remember, the tank is only going to be good as the water we are putting into it. 

  • ISSUEA larger fish may have died, or a rotting plant in your tank and is releasing ammonia as it's breaking down. 

    • RESOLUTION: Remove with a siphon and make sure you get all the decaying matter. Process water changes to get the ammonia down below .25ppm. You can also use Seachem Prime as directed to help with the ammonia spike. Emergency dosages are on the back of the bottle. 

Do you use API test kits and want a little cheat sheet on what to do if your cycle crashes? Download this free chart by clicking the image. 

AquascapeGuide API Emergency Test Chart Cover.jpg
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