nitrogen cycle completed?

Discussion in 'Aquarium Nitrogen Cycle' started by AndyVE, Aug 5, 2014.

  1. AndyVEValued MemberMember

    Hi all.
    am cycling a new tank.
    am wondering if it is cycled or not.
    get the following readings:
    pH : 7
    kH : 4
    gH : 6 or 7
    NO2 : 0.5 or 1mg/l
    NO3 : 25mg/l

    Due to the high level of Nitrate i would guess so?
    But have the impression my nitrit level is also still pretty high?

  2. jdhefModeratorModerator Member

  3. AndyVEValued MemberMember

    How does the nitrate go down without any wc?

  4. Ramses IVNew MemberMember

    Excuse me if i'm wrong but I thought at the end of the Nitrogen cycle you should have a some nitrate. I poked in because I myself have just started in the hobby and I would like to get the right information.;)
  5. AndyVEValued MemberMember

    Exactly...thought it only went down by performing a water change?
  6. ricmccWell Known MemberMember

    At this point nitrates are not really important; what you wish is for 0 ammonia, 0 nitrite, and also to always remember that any tank is only properly cycled to its current bioload.
    If you introduce six, for example, new fish to a tank cycled to a lower bioload, your cycle will be again delayed.
    This is why is it so important to introduce fish on a gradual level, even to a fully cycled tank.
    Frequent W/Cs are the easiest way to remove nitrate, of course, but a level of .25 is really not that unusual-however, a nitrite level such as you mentioned shows more a tank that is closing in on, but not yet cycled, nitrates being the result of the breakdown of nitrite, which seems to not yet to be fully happening..-----Best, rick
    Last edited: Aug 5, 2014
  7. Ramses IVNew MemberMember

    As far as I know it only goes down through WC. I believe having plants help, too.
  8. Adam55Well Known MemberMember

    Live plants do indeed help, and water changes are still the main method of getting them down. I also believe SeaChem makes a product to lower them but I don't really know why anyone would use it.

    And yes, a cycled tank should and will have some nitrate.
  9. AndyVEValued MemberMember

    do not have an ammonia test in my kit (why are they not included in a basic test kit). But bought an NO3 test to supplement my basic kit. Hense the reading above.
    So as long as my nitrite level is not returned to 0 by itself my tank is still in his cycle (if no new fish have been added), but it already has some of the bacteria that convert my nitrite to nitrate. Correct me if my logic is wrong here.
  10. jdhefModeratorModerator Member

    Sorry...I am at work and had to end my last post sooner than I intended.

    When cycling a tank you start off with a rise in ammonia as fish release ammonia into the water (or you use an artificial ammonia source if cycling fishless). After several weeks of having ammonia in the water, a bacteria will grow in your filter media that consumes the ammonia, but releases nitrite as it's waste product. Once you have enough ammonia consuming bacteria to handle all ammonia being produced, your ammonia level will drop to 0ppm.

    After several weeks of having nitrites in the water, a bacteria will grow in your filter media that consumes nitrite and releases nitrate as it's waste product. Once you have enough bacteria to consume all the nitrite that is being produced your nitrite level will drop to 0ppm. At that point you should have nitrtaes, since all nitrites have been converted.

    So if you have rising nitrates and nitrites, that would mean that you have some nitrite consuming bacteria, just not quite enough to process all the nitrite.

    Basically there are two ways to lower your nitrates. One is thru water changes, the other is thru plant uptake. But keep in mind it would take a large amount of plants to remove all nitrate.

    If you are using test strips, I highly recommend you upgarde to a liquid based test kit like the API Master Test Kit for Freshwater. It has an ammonia, nitriite, nitrate and pH test kit included. Plus test strips are notorious for being inaccurtae.
  11. AndyVEValued MemberMember

    Ah thanks for the info.
    I have a Sera test kit (drops) but that only contains pH, kH, gH and NO2. Also added an NO3 test to it. Have strips also but only use them as a quick reference (mainly for pH, gH and kH...since they seem on par with my liquid test kits results).

    will also buy ammonia one tomorrow.

    Was wondering already since they talk about at least 2 weeks up to 2 months to cycle. But am just at my 2nd week.
  12. AndyVEValued MemberMember

    Did ammonia test today (got it from the store). No ammonia present or at least negligable (depending on how accurate the colour of the liquid has to match the colour of your score card).
  13. petaddictionWell Known MemberMember

    That should mean you're almost cycled. Once the nitrite is gone and if the ammonia stays at 0, you'll be cycled. :)
    You'll want some nitrates to be there too as those get taken out through water changes and a little by live plants.

    Sent from my iPhone using Fish Lore Aquarium Fish Forum
  14. AndyVEValued MemberMember

    Today my ammonia level was 0,003 and nitrites was 0
    hard to read the score since I am not sure my pH was the colour for 6.5 or took 7 for the test (since that should give me the worst result if i can follow the manual correclty...)

    so guess this means my tank is cycled?
  15. Adam55Well Known MemberMember

    Very possibly. Is this fish-in or fishless? If fishless, what do you dose ammonia to?
  16. AndyVEValued MemberMember

    Hi Adam,
    started 1 week (24/7) without with some starter product. But then added 4 corydoras trilineatus (and added 2 couple of days ago since non of the first died).
  17. PhishphinWell Known MemberMember

    What's the name of the starter product?
  18. AndyVEValued MemberMember

    Sera filter biostart
  19. PhishphinWell Known MemberMember

    I would just wait until ammonia readings were absolute zero, nitrites were absolute zero, before adding two more. If you are still registering ammonia, or if it spikes a little, it means the bacteria colony (which is definitely present) is not the most established and is bouncing around a bit. I'm not familiar with Sera filter biostart so I can't speak to its effectiveness, but I know the bacteria colonies in a bottle (while mostly effective) can take some time to firmly establish. Once everthing is at a perfect zero (except for nitrates), do a big water change. If nitrates are below 20ppm, you can add two more of the cories, just be sure to continue to monitor everything and try to get the nitrates even lower. :)

    Good work being a responsible fish keeper!
  20. AndyVEValued MemberMember

    Idea is to keep this combo a month or so as is.
    Eventually add a dozen cardinal tetra's (probably in two steps).

    Am taking measurements almost on daily basis for now.
    so if the next week my levels keep dropping i might change it to weekly (unless my fish start to behave weird).

    ps nitrates are at 10mg/l
    Last edited: Aug 9, 2014

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