Zero nitrite? 2 weeks in - seems an odd result

Discussion in 'Water Chemistry' started by LeTigra, 8 Aug 2009.

  1. LeTigra

    LeTigra Member

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    I have a potentially silly question so please don't throw anything at me....
    I'm cycling a tank. Although I'm not new to keeping fish this is the first time I've properly cycled a tank because the last time I had a new tank was years ago and I didn't know what I was doing. Now I'm doing it properly but I'm confused.

    I have a Rekord 800 - 29gal I think. I used substrate from my old tank and added a piece of wood covered in Java fern from that same tank. I pulled a few Vallis plants and an Anubias from there too and bought a few new plants - I'm not sure what they are but they're stems and they're growing fast which is what I wanted. Filled tank with fresh dechlorinated water. Have been adding flakes and at one point added a whole cube of frozen used-to-be-alive food (some form of worm). I thought the old substrate would probably contain a fair amount of "rubbish" to provide the necessary ammonia.

    Tanks been running for 2 weeks today. Lights on approx 10 hours a day for the plants, temp set at 24C. Cycle being added a splash at a time every few days My Nitrite is measuring 0. The test is a liquid one not a dip-strip. I didn't get an ammonia test because I figured I coud do this with only a Nitrite test - I would see a peak in Nitrite which would then go down to zero and as long as I was still feeding my good bacteria everything would be ok til I added fish.

    Are my plants effecting my "fishless" cycle? I didn't want to go down the route of having to add pure ammonia but still - shouldn't I be seeing SOME nitrite 2 weeks in?
    My filter has one of those green nitrate removing sponges in it - this wouldn't effect nitrite levels though would it?
     
  2. aaronnorth

    aaronnorth Member

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    well the amount of NH4 produced by rotting food the plants will utilise it! Anything that is left over probably wont be enough to make a difference to bacteria levels, especially when you add fish as it will be more than the bacteria can handle anyway :rolleyes:

    There is 2 ways you can go about cycling a tank,
    1) fishless cycle with ammonia (daily)
    2) silent cycle - fcover 75% substrate with fast growing plants, add a few fish and any ammonia will be utilsed by the plants, with "the rest" going towards filter bacteria development. It is also advisable to use a form of ammonia remover in the filter.
     
  3. LeTigra

    LeTigra Member

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    So the tank won't cycle because I have plants and not enough ammonia? So I can remove the plants to do a proper fishless cycle, or up the ammonia
    Why does a silent cycle work then? If there's so many plants how can a few fish produce anough ammonia? Do fish just produce a lot of ammonia?
     
  4. GreenNeedle

    GreenNeedle Member

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    A silent cycle works because in a fully planted tank the plants are doing what the bacteria in a plantless/lightly planted tank would be doing........removing the ammonia!!!

    AC
     
  5. LeTigra

    LeTigra Member

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    I do understand that.
    What I meant was - if my not-densely-planted plants are using up any ammonia being produced by rotting food and whatever cr*p was in the old substrate, then how come in a densely planted tank with just a couple of fish as an ammonia source is there enough ammonia left over after the plants have used what they need, to feed filter bacteria? Those couple of fish must be producing a lot of ammonia for that to work. I don't want to have the obvious shouted at me like I'm a stupid person. I come here because people on this forum seem to actually know what they're talking about and I wanted some advice. Don't assume that because I asked for advice that you are somehow a superier human being to me
    Cheers
     
  6. aaronnorth

    aaronnorth Member

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    because as soon as ammonia is produced, it isnt instantly utilised by the plants! ;) It does pass through the filter and the bit that does pass through goes towards filter bacteria development. Taht is why you should add about 6 fish per week, so it isnt a sudden jump/.
     
  7. LeTigra

    LeTigra Member

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    Ok cool. Thank you, it makes sense now
    I'm going to have to review my cycling method
     
  8. Ed Seeley

    Ed Seeley Member

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    If you're putting food in and not getting a nitrite reading then your tank is mature enough to stock a few fish. If you think about it then adding fish will not change this (as long as you keep on adding similar amounts of food) just because the fish are eating the food! You're still putting the same amount of waste into the tank! Just take it really slowly and add a few small fish and feed them very lightly to start with.

    I think the reason your tank has cycled so quickly is the old substrate. The surface layers of substrate contains loads of bacteria that will process the waste so you've given your cycling a huge jump-start. It's nearly as good as transferring mature filter media over to a tank which will help a tank cycle in days.
     
  9. LeTigra

    LeTigra Member

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    Nice!
    Thats great, thanks Ed
    I'll leave it another week just to make sure and maybe add a couple of fish next weekend
     
  10. George Farmer

    George Farmer Founder Staff Member

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    Bear in mind test kits can be very unreliable too, especially nitrate.
     
  11. Fred Dulley

    Fred Dulley Member

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    Not that we can have that being said in PFK mag. :?
    Or indeed their forum...
     
  12. LeTigra

    LeTigra Member

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    I've only got the one type of test so I'll take a sample along to a fish shop for a 2nd opinion then just to make sure its all ok
    Thanks
     
  13. Ed Seeley

    Ed Seeley Member

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    Actually I think George might be referring to a range of tests Jeremy Gay did on the accuracy of test kits in PFK. They can show widely ranging results from the same sample water as you need to be incredibly accurate with the drops and water amounts to get accurate results with liquid test kits when you're dealing with such small quantities. IME though if you have some of the chemical present you tend to get some trace of colour and, if anything, it's more likely to over-estimate the amount of Nitrite/ammonia than under-estimate it.

    As long as you take it steady now with your stocking I'm aure you will be fine LeTigra. :thumbup:
     

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