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First fishless cycle

Discussion in 'Cycle your Tank' started by EMahn, Feb 9, 2018.

  1. EMahn

    EMahn New Member

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    I am a longtime aquarist (freshwater community), but much of that was a decade or more ago. I am setting up a new freshwater 65 gal tank and I am dosing with Ammonia to cycle. Tank has ~3" gravel substrate and a Eheim Pro 4 600 canister using the supplied media (I have no access to seeding material). Temperature is 28C (82 F). All substrate and media were carefully rinsed before using. I dosed with Seachem according to instructions when I started the cycle.

    Cycle was started about 2 weeks ago. I dosed ammonia to ~4 ppm. I haven't seen much if any drop in ammonia and no nitrites. I got impatient with no changes, so did some additional research and I decided to measure kH (not originally considered). I got an API kH test kit and saw that my kH was very low (0-50ppm). After finding a formula online, I dosed some baking soda to raise the kH. Either the formula was off or I miscalculated, but this had a bigger effect on kH than I was looking for. It takes 8 drops to turn yellow with the API kit (8 dkH). The pH was also affected by the bicarbonate more than I expected, moving from 6.8 to 7.8.

    I think these levels kH and pH are good by themselves, but it was a sudden change for the tank chemistry.

    Questions:
    1. Will the big change in kH/pH have an adverse impact on completing the cycle?
    2. Should I make an intervention like a PWC at this point or let it ride?

    Thanks for your help.

     
  2. docpark

    docpark New Member

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    Hi EMahn:

    At this stage I'd recommend that you focus on establishing the cycle and not worry about the ph and hardness. It's true that a higher carbonate hardness is associated with a more stable ph, but your original ph of 6.8 is fine for growing the nitrifying bacteria and getting the cycle up and running. I don't know if a sudden swing from 6.8 to 7.8 necessarily did in your bacteria, but that's an awfully big change and probably didn't help.

    Registering high ammonia and zero nitrites or nitrates is not at all unusual at the two-week mark of a cycle. You could try switching to another bacterial additive like Tetra SafeStart after a PWC, but to be honest it's probably just a matter of patience at this point. A big water change is likely to result in another wide ph swing; a series of smaller ones might be better if you want to get the water back where it was.
     
  3. essjay

    essjay Member

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    The baking soda (provided it is baking soda and not baking powder) won't do any harm during the cycle. But when it is complete you need to do a huge water change to remove it all before getting fish.

    As for the cycle itself, 4 ppm is a bit on the high side. 3 ppm is all you need. Have you found the method on here http://www.fishforums.net/threads/cycling-your-new-fresh-water-tank-read-this-first.421488/ The old 'add ammonia every time it drops to zero' method made so muc nitrite that it stalled the cycle; the method in that link was devised so that if followed to the letter, nitrite can never get high enough to stall the cycle.
     
  4. EMahn

    EMahn New Member

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    Thanks for the helpful responses.

    Yeah baking soda (I enjoy cooking, so the difference from baking powder is clear).

    When it is all done, I will actually need to dose with soda again since my water is so soft. At least this time I will be more informed about correct dose.

    The cycling link has a lot of detail. So many subtly different instructions available on fishless cycles!

    So if I get this one, the unique features are:

    > Start with 3 ppm ammonia
    > Wait for ammonia <= 0.75 ppm AND nitrite >2 ppm.
    > "Snack" ammonia dose for Dose #3
    > Subsequently dose after <= 0.25 ppm AND nitrite >1 ppm until can zero ammonia and nitrite in 24 hours

    In fear of just over managing this, I am going to let this ride with current levels. I'll pick up with the instructions once I see ammonia/nitrite levels match above.
     
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  5. essjay

    essjay Member

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    I agree, leave the 4 ppm ammonia as it is and when you reach that stage, continue with the instructions.

    I would be wary of adding baking soda when there are fish in the tank. At the risk of saying what you already know, baking soda is sodium hydrogen carbonate (old name sodium bicarbonate) and adding sodium is not a good idea. It adds a mineral to the water which is not found in natural fresh water over trace amounts. If you want to raise KH use dolomite, either as a piece of rock as decoration, or a small bag of crushed dolomite in the filter. Dolomite has the advantage over limestone, coral and aragonite that it contains magnesium as well as calcium. It will also raise the GH and pH as well.
    Byron has very soft water and he adds nothing to his tanks. He'll be able to advise you better on how to cope with soft water.
     
  6. EMahn

    EMahn New Member

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    Thanks for your thoughts about managing kH.

    So this is off topic from cycling, but it is relevant to my post. If the primary outcome of increasing kH is to tame pH creep, would a pH buffer such as SeaChem neutral regulator provide the same purpose? To be clear, this would be post-cycle. Dosing with a buffer seems more predictable (and familiar, at least to me) than bicarb/crushed coral/dolomite.
     
  7. essjay

    essjay Member

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    My KH is slightly higher than yours at 3 deg - or 53 ppm - and all I do do is weekly 50% water changes which replenishes the KH level.

    About a decade ago I was very lax about water changes, doing 25% roughly once every 3 weeks, and I had a pH crash - it dropped of the bottom of the scale so it was somewhere below 6.0 from 7.5. I was advised on a different forum to add remineralisation salts of the kind used with pure RO water. But I don't like adding things to my tank unnecessarily so I just changed my water change regime and haven't had a pH problem since then.

    Water changes, provided they are weekly and big enough, are all you actually need.
     

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