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Results 1 to 10 of 42
  1. #1

    Default trouble with fishless cycle

    0 Not allowed!
    Hello all,
    I am cycling my tank without fish. At this stage I have ammonia dropping from 3ppm to 0.25ppm in 24 hours, and 5+ppm nitrite and 5ppm nitrate. So I believe I have beneficial bacteria to convert ammonia to nitrite, and am just starting to establish beneficial bacteria to convert nitrite into nitrate. However, the problem I am having is that ammonia will drop quickly to 0.25ppm, but even after another 12-24 hours waiting, the levels arent dropping any lower than 0.25ppm. the first ammonia drop in my cycling went to 0ppm, i dosed back to 3ppm. then from then onwards they have dropped to 0.25ppm and stayed there. the last few doses I have dosed back up to 3ppm even though the level only went down to 0.25 not 0ppm, despite me leaving it a day to drop from 0.25 to 0. It races from 3ppm to 0.25, but seems to stall and not go fully down to 0. What is happening?!?! why wont my ammonia reach 0?
    I use the API master freshwater liquid test kit, with throughly washed test tubes, i vigorously shake the bottles before dropping and follow instructions carefully and also give the test tubes a hard shake so it cannot be faulty test results. What am i doing wrong?

  2. #2


    0 Not allowed!
    If you started your cycling process using 3ppm of ammonia, then you should only bring it back up to a little over 1ppm once you get your nitrite spike or you can slow things down a little (worst case situation). I would suggest that would be the level you should now dose back up when the level hit 0ppm

    You also have to keep in mind, it usually takes longer to grow the nitrite eating bacteria than it did the ammonia eating bacteria

    There is a link below in my sig to a really good thread that also explains how to fishless cycle
    If you take your time to do the research FIRST, you can successfully set-up and keep ANY type of aquarium with ease.
    "Not using a quarantine tank is like playing Russian roulette. Nobody wins the game, some people just get to play longer than others." - Anthony Calfo
    Fishless Cycle Cycling with Fish Marine Aquarium Info [URL=""]

  3. Default

    0 Not allowed!
    If I'm readying your post correctly, when your ammonia initially dropped to 0, you redosed to the same dosage that you started with. The stickie on fishless cycling clearly states that once you see nitrites and ammonia has dropped to 0, then only add ammonia of one/half of your original dose.

    What I would do is wait until the ammonia drops to 0. It may take more than 24 hours. When it does, THEN redose but again, only to 1/2 of your original dose.

    it would help to know how many gallons we're talking about. if it's a smaller tank, dosing to three on your original dose might have been too high.
    30 g FW planted:corys, female ABNP, blue angel, harleys, zebra danios, rummies,
    15 g FW planted:2 male guppies, neons, pygmy corys, clown pleco, 4 types of shrimp, assassin snails
    90 Gal Journal:
    fishless cycling:
    fish in cycling:

  4. #4


    0 Not allowed!
    sorry for the confusion: I originally dosed the tank to 5ppm, when the ammonia first hit 0 i dosed to what looked a little darker than 2ppm on the test chart but not as dark as 4ppm so I estimated it was 3ppm so I have been doing half doses of ammonia. it is a 100L/26gallon tank

  5. Default

    0 Not allowed!
    Got it
    You've initially dosed way too high for a 26 gallon tank. I would have dosed to 2 not 5.
    Stop dosing and see if your ammonia doesn't drop to 0 within a few days. If it does and you're still showing nitrites, then only dose to 1.

    If it doesn't drop, then I might suggest a 50% water change. It's not what you'd normally do during a fishless cycle, but since you dosed way too high you may need to get some of the ammonia out of the water that way.

    Someone else may have a better suggestion, but see if waiting a few days without dosing works first.
    How long have you been cycling btw?
    30 g FW planted:corys, female ABNP, blue angel, harleys, zebra danios, rummies,
    15 g FW planted:2 male guppies, neons, pygmy corys, clown pleco, 4 types of shrimp, assassin snails
    90 Gal Journal:
    fishless cycling:
    fish in cycling:

  6. Default

    0 Not allowed!
    You, you've DEF dosed too high.

    Essentially you're trying to grow more bacteria than your filter can hold. You have a few options here. Wait until it drops all the way down, and do a much lower dose-- as fm said, do a 50% W/C to speed that process up-- or if you WANT, you could add another filter or media and you've got extra bacteria. The last option would probably take longer though.

    Another thing---- My test ALWAYS reads .25, even when it is zero. I see that yours has actually gone to the 0 color though, so that probably doesn't apply to you.
    130g: 4 Angelfish, 2 Roseline Sharks, 12 Conga Tetras, 5 Kuhli Loaches, 1 Otocinslus, 1 Corydora

  7. #7


    0 Not allowed!
    Thanks for the help, I have been cycling for 3.5 weeks

  8. #8


    0 Not allowed!
    Quote Originally Posted by pckroeger View Post
    I originally dosed the tank to 5ppm,
    That was the first mistake - dosing that high. In peer reviewed research, the best level was found to be 1 ppm ammonia (but I see no issue with 2 ppm.) The reason is that too much of one type of bacteria tends to grow (ones that convert ammonia to nitrite.) That all said, the issue is what to do now?

    First, stop dosing at 3 ppm ammonia and do not dose if the ammonia is 0.25 ppm (but be very sure the kit isn't calling zero 0.25 ppm.) Next, raise the tank temperature to at least 82 F (I used 88 F with good results.) Then add an air stone or bubble wand to increase oxygen in the water (when you get fish, those are very helpful to use, or at least have on hand for other treatment issues.) This should all help the nitrite to nitrate converting bacteria to grow and drop those nitrites levels to zero.
    Last edited by Cermet; 03-02-2013 at 11:58 AM.
    Knowledge is fun(damental)

    A 75 gal with eight Discus, fake plants, and a lot of wood also with sand substrate. Clean up crew is down to just two Sterba's Corys. Filters: continuous new water flow; canister w/UV, in-tank algae scrubber!! Finally, junked the nitrate removal unit from hell.

    For Fishless cycling:

  9. #9


    0 Not allowed!
    how do I test if my test kits are showing 0ppm as 0.25ppm??
    i tested my regular unconditioned tap water and it showed 0.5ppm
    then i tried my 'filtered' tap water from the kitchen and it still showed 0.25ppm
    how do i know if this is just ammonia in my tap water, or if it is the test showing 0 as 0.25??

  10. Default

    0 Not allowed!
    I tested bottled drinking water, like Dasani or Aquafina. No matter WHAT kind of water I test I get that reading.

    If you've already had a reading of 0 though, I'd say you don't have this issue.
    130g: 4 Angelfish, 2 Roseline Sharks, 12 Conga Tetras, 5 Kuhli Loaches, 1 Otocinslus, 1 Corydora

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