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Nitrate Readings

Discussion in 'Water Chemistry' started by Big B, Mar 22, 2017.

  1. Big B

    Big B New Member

    Joined:
    Mar 22, 2017
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    Country:
    Australia
    State:
    Queensland
    City:
    Gold Coast HINTERLAND
    Hi Folks.
    I am relatively new to this.
    Was just wondering if you could give me some advice here.
    I have a system with IBC chop and flip design about 700 litres of water and 300mm media bed with Clay pebbles in it.
    I have 15 Jade perch and 12 Small Redclaw in the bottom.
    I started cycling the system around four weeks ago and planted lettuce Basil and Assorted Greens.
    for the first 3 weeks I added a capful of Seasol and just recently added a teaspoon of chelated iron.
    I was hoping you could give me an indication of the water chemistry.
    From day one every two days I have done a water test of PH Ammonia and Nitrite and Nitrate.
    PH HAS ALWAYS REMAINED AROUND 7.6
    AMMONIA WENT UP JUST ONCE TO 0.25
    NITRITES WENT UP TO 2.0PPM
    AND NITRATE LAST WEEK WAS 20PPM NOW THIS WEEK ITS UP TO 80PPM.
    Should I be worried or is this the so called cycle or do I need to add additional Plants.
    Your thoughts would be appreciated.
     
  2. Yabbies4me

    Yabbies4me Administrator Staff Member

    Joined:
    Jul 27, 2010
    Messages:
    5,881
    Country:
    Australia
    State:
    W.A.
    City:
    Perth
    Hi Big B, welcome to the forum.

    A Nitrate level between 0.0ppm and 40ppm is fine. If the system sits constantly above 40ppm it is overstocked IMO and you need to: (a). Add another grow bed, or (b). Reduce feed rate, or (c). Remove some fish.

    At 80ppm smaller leafy greens, such as lettuce, will start to become bitter. At 160ppm seedling growth of many plants will be inhibited, flower set and fruit development can be affected, and long term exposure at this level can affect the fish health. It has also been suggested that at 160ppm the flesh of the fish can develop a muddy taste.

    Your system is definitely overstocked and the Nitrate issue is only going to get worse. Your Ammonia levels may be 0.0ppm at the moment (should be), but as the fish grow the Amm level is going to become an issue as well.

    An IBC type grow bed with a 300mm gravel depth will have a total gravel volume of around 330L, and flooded to around 250-260mm (you should allow a 40-50mm dry layer in your GB's) will have a wet gravel volume of around 280L. Jade Perch require 25L+ of wet gravel per fish to get them safely through to a plate size of about 500gm... So your system in it's current form is good for a maximum of 11 Jade Perch.

    I would suggest adding another GB a.s.a.p.

    Also, were your fish in the system from day one, or did you fishless cycle?... If you cycled with the fish in the system, did you add any salt once your Nitrite level exceed 1.0ppm?... Has your Nitrite level dropped to 0.0ppm?

    Cheers!
     
  3. Big B

    Big B New Member

    Joined:
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    Country:
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    City:
    Gold Coast HINTERLAND
    image.jpeg Hi yabbies4me
    Just looking at my history of tests which I have attached.
    I cycled with plants for about two weeks fish less using a cap of sea sol every day or so.then on 7th March I added 12 redclaw fingerlings and 15 jade perch fingerlings.and also added a twin valve aerator.
    As you can see by the attachment the jump.could this just be as it may not have cycled properly yet.going by murray hallum info he mentioned 10 fish per 100 litres so I thought I would be well in the OK range.i am thinking of running a nft length of around 3 Mtrs with plants every 35cm would this help? Your info is well received.regards brett
     
  4. Yabbies4me

    Yabbies4me Administrator Staff Member

    Joined:
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    W.A.
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    First things first... With the Nitrites sitting at 2.0ppm your fish will be suffering, I would be adding sea salt (pool salt) at 1gm/Ltr immediately. It reduces the harmful effects of the N02.

    In regards to adding NFT channel, the extra plants will help with reducing Nitrates, but it will do very little towards helping with with the overstocking issue and future Ammonia issues.

    A system's safe fish stocking capacity is primarily determined by the amount of beneficial Nitrifying bacteria in the system (otherwise known as it's bio-filtration capacity), not the water volume. The wet gravel is used because it provides a large surface for bacteria colony development.

    A system is not regarded as being fully cycled and safe for fish until both the Amm and Nitrite have dropped to 0.0ppm

    Cheers!
     
  5. Big B

    Big B New Member

    Joined:
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    Country:
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    Gold Coast HINTERLAND
    Hi Yabbies4me
    I did as you suggested last night and slowly added 550g of salt as I actually have 550 litres of water I saw a line on the IBC last night not 700 like once thought.
    I checked on the fish this morning and they all seem very spritely so thats good.I did a water test also last night and it was exactly the same as two days prior so it will be interesting to see what the result is in a few days time.on another note as your name suggests Yabbies4me are you well informed of keeping Redclaw.
    I put Twelve redclaw in the tank two weeks ago but can only seem to find one or two ,the rest are like they have dissapeared there is almost 400mm wall and I have put a plastic sleeve over the pipes to stop them escaping.The Redclaw were similar size to the Jade perch fingerlings I put in at the same time.
    So i could probably rule out escape so would the Jade perch eat them?
    I am also adding some nft system to it on saturday and I have cut the feed rates right back for now to see if it helps balancing the system out.
    I really appreciate your assistance its a great thing Im involved in here and I love it.
    it makes it so much better when there are people like yourself that gives great advice as there is so many you tube clips and different info it boggles your mind.
    Good day and thanks Big B
     

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