The Planted Tank Forum banner
1 - 8 of 8 Posts

·
Registered
Joined
·
60 Posts
Discussion Starter · #1 ·
I am interested in learning more about the freshwater nitrogen cycle and how to support denitrification bacteria. I often find articles that look great and have the level of depth I'm looking for, only to discover it's about a marine environment.


Is the nitrogen cycle of the saltwater tank so different from the freshwater tank? I get that each environment supports it's own species of bacteria, but are the bio-mechanics essentially similar?
 

·
Registered
Joined
·
66 Posts
There are a few good tutorials online. Just add "freshwater" to your search. Ammonia converts to Nitrites which converts to Nitrates. Then you do a water change to remove the nitrates.

Fishless Cycle: You can buy a pure Ammonia at the hardware store (without additives or detergents). Shake the container at the store; if it foams like it's soapy, then don't buy it. Add this to a new aquarium (without any livestock) to about 40ppm. Check levels every few days until they start to drop or Nitrites start to rise. Check Nitrites and Nitrates. Eventually, you should get to the point where 2ppm of Ammonia can be cleared, and all Nitrites can be cleared, in about 24 hours. Then you're fully cycled. WARNING: This can take *FOREVER*, like 1-3 months.

Better: Start the fishless cycle process, but then scape your aquarium with a TON of plants. The plants will help remove all the ammonia and allow you to add fish before you're totally cycled. Don't add any livestock unless ammonia and nitrites are zero. Nitrates should under 40ppm, ideally around 5-10ppm. Keep an eye on it - if you see any ammonia or nitrites, then do a water change.
 

·
Registered
Joined
·
60 Posts
Discussion Starter · #3 ·

·
Registered
Joined
·
1,769 Posts
Fishless Cycle: You can buy a pure Ammonia at the hardware store (without additives or detergents). Shake the container at the store; if it foams like it's soapy, then don't buy it. Add this to a new aquarium (without any livestock) to about 40ppm.
Pretty sure you meant 4 PPM and not 40 PPM for others following along in the future.
 
  • Like
Reactions: Blue Ridge Reef

·
Registered
Joined
·
620 Posts
In general, I find marine aquarium articles (especially reef aquarium articles) to be more in-depth than freshwater aquarium articles. I believe this is out of necessity, because reef aquariums are much more complex than freshwater aquariums.

The article you cite covers topics such as live rock and deep sand beds, features that we do not utilize in planted tanks. These features serve to reduce nitrates into nitrogen gas in a reef tank, while this would be counter-productive in a planted tank, as we strive to keep nitrates around 5-10 ppm. Reefkeepers strive for nitrates to be as low as possible to prevent nuisance microalgae from growing.

However, the biomechanics are essentially the same between marine and freshwater systems.
 

·
Registered
Joined
·
2,343 Posts
It’s never a waste of time to understand biological processes. But as pointed out above understanding how they pertain to any particular system and how to implement them in that system is as important as knowing the basic principle.
 

·
Registered
Joined
·
12,735 Posts
I really just want to know if I'd be wasting my time studying articles like this one that refers to the Cycle in a marine environment:
Nitrogen Cycling Revisited: Sand, critters, carbon, and why you may be under-feeding your tank

Yes....if you want to port it to freshwater, though like you know concepts apply..
Starting w/ the tanks pH means the dynamics are different..Few tanks are alkaline and most are neutral to slightly acidic..



Ocean acidification, the result of roughly a third of global CO2 emissions dissolving into the seawater and lowering its pH, has complicated and poorly understood consequences for ocean ecosystems. Scientists already know that a drop in ocean pH affects the carbon cycle, reducing the carbonate ions that organisms like corals, mollusks and crustaceans use to build shells and external skeletons. Now, a new study shows that a CO2-induced increase in acidity also appears to disrupt the marine nitrogen cycle. The finding, to be published December 21 in the Proceedings of the National Academy of Sciences, could have ramifications for the entire ocean food web.
https://blogs.scientificamerican.co...cation-may-disrupt-the-marine-nitrogen-cycle/


Then comparing our tiny ecosystems to global ones has its own set of problems..


Not discouraging "learning" but the parameters are different..


This brings us back to pH. If the pH drops below 6 in a given system, the Nitrosomonas bacterium will not adequately process the ammonia in the water. If the pH eventually gets low enough, the nitrogen cycle will cease to function all together. If the pH levels rise above 9, as mentioned earlier, very high concentrations of toxic ammonia (NH3) are present. The nitrogen cycle itself tends to reduce the pH of a system. Most freshwater fish would fall into a pH range between 5.5 and 7.2, with a few exceptions at both the high and the low end. It is not just fish that need to have an appropriate pH to thrive. Live plants do best in a pH range between 6.5 and 7.5. Beneficial bacteria prefer a slightly higher range, from 7.0 to 8.0. In general, a good pH range that would satisfy most fish, along with live plants and bacteria would be 7.0 to 7.2. It is important to note that pH in the aquarium is not completely stable, with small fluctuations occurring throughout the day and night. Many things can affect the stability of the pH within a system. Aeration, gravel, fish tank decorations, temperature, and nitrate levels are just some of these.
https://petcentral.chewy.com/the-role-of-ph-in-the-aquarium-nitrogen-cycle/

Personally I think it is "questionable" that reef tanks are more "complex" since really many of the same things effect both.
food, minerals, water quality, are all fairly similar in concept.
The fact that one can discuss things the "proper" ratio of Ca to Mg tells you its sort of as complicated as you care to make it.
Need to think about that a bit though..
 
1 - 8 of 8 Posts
Top