# Nitrogen Cycle for Dummies



## DaveK (Jul 10, 2010)

I read your article, and it's very good, but I would suggest a few changes.

The nitrogen cycle doesn't really end. It becomes established so that bacteria can process the amount of ammonia produced by the livestock. I think that needs clarification.

Using fish to cycle a tank is ok, but I feel methods that don't use live fish to cycle a tank should be mentioned. Many beginners either add too many fish or not enough and run in to the problems you mention. It would help to give an example of how may fish you would typically add to start the cycle. Something like "When I set up my 20 gal tank I used 3 cory cats", would help beginners judge the fish correctly.

Keep up the good work.


----------



## ReefkprZ (Aug 21, 2010)

that is a great article and you obviously put a lot of work into it.

I do agree with dave that you should make sure to point out that the "cycle" doesnt end, it reaches an equilibrium, and even though your tank is "cycled" it is still possible to have ammonia spikes if you add too much food or too many fish to quickly, even after the initial cycle.

Great job roud:


----------



## Hoppy (Dec 24, 2005)

Another thing to change: nitrates are not toxic to plants. And, the level of nitrates that harm fish is much higher than 20 ppm, more than 10 times higher. 

All living things establish colonies that match their available food supply. The bacteria that convert ammonia to nitrites, then to nitrates, also form colonies that match their food supply - ammonia. This argues that fish need to be gradually added to any aquarium. Clearly that doesn't mean adding just one very large fish to a small tank. It does mean adding a few small fish at a time.

Growing plants consume a lot of nitrates, but they also consume ammonia, and even prefer ammonia to nitrates. So, if you plant the tank heavily from the start, then wait until those plants are growing, you will not build up ammonia in the water by adding few small fish - the ammonia produced by the fish will immediately be consumed by the growing plants. That heavily planted tank will establish its own nitrogen cycle if you add 2-3 fish a week or so after first planting the tank, if the plants are growing, then add a few more fish every week until you have the tank stocked. But, the first step is to heavily plant the tank - about one stem plant every square inch of substrate.


----------



## littlefish (Aug 6, 2010)

thanks for your cooperation, I understand your point


----------



## RipariumGuy (Aug 6, 2009)

Out of curiosity, did you ask all those people if you could use their pictures on your blog? 

Just wondering, because alot of them I have seen before, and there is nothing saying that they are not yours. 
Regards,
Jake


----------



## timwag2001 (Jul 3, 2009)

Hoppy said:


> Another thing to change: nitrates are not toxic to plants. And, the level of nitrates that harm fish is much higher than 20 ppm, more than 10 times higher.
> 
> All living things establish colonies that match their available food supply. The bacteria that convert ammonia to nitrites, then to nitrates, also form colonies that match their food supply - ammonia. This argues that fish need to be gradually added to any aquarium. Clearly that doesn't mean adding just one very large fish to a small tank. It does mean adding a few small fish at a time.
> 
> Growing plants consume a lot of nitrates, but they also consume ammonia, and even prefer ammonia to nitrates. So, if you plant the tank heavily from the start, then wait until those plants are growing, you will not build up ammonia in the water by adding few small fish - the ammonia produced by the fish will immediately be consumed by the growing plants. That heavily planted tank will establish its own nitrogen cycle if you add 2-3 fish a week or so after first planting the tank, if the plants are growing, then add a few more fish every week until you have the tank stocked. But, the first step is to heavily plant the tank - about one stem plant every square inch of substrate.


 
i know all about the adding fish slowly in reference to the cycle, hoppy. would you say the same that you should be carefull when removing plants if you have a heavily stocked / heavily planted?


----------



## Hoppy (Dec 24, 2005)

timwag2001 said:


> i know all about the adding fish slowly in reference to the cycle, hoppy. would you say the same that you should be carefull when removing plants if you have a heavily stocked / heavily planted?


No, because by then you also have lots of nitrifying bacteria growing all over everything in the water. However, I only keep small fish, not Discus, big angel fish, etc. I think if you have a tank with lots of big fish, you do have to be careful not to reduce the total plant mass down to 10% of what it was. I know regular pruning doesn't cause ammonia problems.


----------



## Hookahh (Aug 24, 2010)

Thanks for the info littlefish.


----------



## LilGreenPuffer (Sep 23, 2010)

If I was cycling with fish (which I never do), I'd start testing ammonia on the first day. Some people have ammonia spikes way before then, for some odd reason.

Nitrites can actually be MORE lethal than ammonia - they affect the neurological system, and they leech oxygen from the bloodstream.

I would also mention that when cycling with fish, you must do enough water changes to keep ammonia and nitrites below .25ppm. You might also want to cover the fact that some fish cannot tolerate a cycling tank, such as pufferfish or elephant-nosed fish - such species usually cannot survive for long with even trace ammonia or nitrite.


----------



## timwag2001 (Jul 3, 2009)

All living things establish colonies that match their available food supply which means that they are only consuming what the plants arent. so plants are consuming ammonia, if you cut them back there would be more ammonia than the colony of bacteria right?


----------



## LilGreenPuffer (Sep 23, 2010)

Yes. But whether or not there would be a significant impact would depend on how many plants you removed.


----------



## timwag2001 (Jul 3, 2009)

but a mini cycle is very possible, even if you cut it back by lets say 25%, wouldnt you think?


----------



## LilGreenPuffer (Sep 23, 2010)

Yep.


----------



## ILoveMyTank (Jul 15, 2010)

Hoppy said:


> But, the first step is to heavily plant the tank - about one stem plant every square inch of substrate.


Ok for those of us who are idiots ????? I'm about to plant my tank.... How do you figure how many square inches of substrate ? I was multiplying 72 inches ( length) by 18 inches ( width ) but ther is no way that can be right because that would be 1296. Help !!!!!!


----------



## timwag2001 (Jul 3, 2009)

just plant the tank the way you want and do a fishless cycle


----------



## Hoppy (Dec 24, 2005)

If you watch someone who is expert on planting a new tank you will be amazed at how long it takes, and how many stems of plants get planted. I know that I was, anyway. Stem plants should be planted one stem at a time, even if it is HC. The tank I watched being planted was about a 40 gallon, as I recall, and the process took hours. Long stems were cut in half or thirds, and each piece planted by itself.

A big tank, like a 72 inch by 18 inch footprint tank does take a huge amount of stems. You can't plant 3-4 bunches, and expect those few plants to keep ammonia in check. It's like expecting to plant 40 acres of onions with a handful of bunches of onion sets, because that's what you would use for a backyard garden. Big tanks are almost farms!

I'm not suggesting that this is the only way to "cycle" a tank. It is just a good way, but if you can't do this, then you should establish a bacteria colony by other methods, before adding even one fish.


----------



## davido (Jul 9, 2014)

So I've cycled my new planted tank for exactly 13 days now. Its a 16 gallon tank - everything is new, pump and all. The tank is light to moderately planted and I watched terrible algae blooms. I'm using ADA Amazonia soil.

The first water tests I took was on day 10 after planting/flooding, And I found :-
1) Ammonia (1ppm)
2) Nitrites (5 ppm)
3) Nitrate (160ppm)
4) CO2 was insufficient
5) PH was 6.

So I did a partial water change (50%), added a bit more plants, added more bio rings and cycling bacteria, and increased CO2. I also pulled out some algae. And reduced the light to 4 hours.

On day 13, I found :-
1) Ammonia zero
2) Nitrites (0.25 ppm)
3) Nitrate (80ppm)
4) CO2 was normal
5) PH was 5.5
Algae was still present, but not as bad as previously.

Tomorrow will be day 14 and I'm thinking my Nitrites will likely be zero (will test first).
If my Ammonia and Nitrites is zero, and Nitrate a bit lower (maybe 60ppm), does this mean I can now add fish? Because I'm thinking of adding six tetras.

To prepare for the tetras, I plan to do a 70% water change to get rid of excessive nitrate and to increase PH (it will likely go to PH 6). And pluck out some algae.

I know you mentioned cycling takes at least 30 days, but that article was written in 2010 and there was no mention of adding cycling bacteria (this came with my bio rings). So in just 14 days my tank has most likely reached zero ammonia and zero nitrites.

Is it safe for me to add tetras? I plan that they are permanent inhabitants.
Am I on the correct path to do this at day 14 and is it right to do a water change before adding fish?

This is my first time cycling a planted tank.

Thanks.


----------

