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New system, high PH and plants stopped growing

Discussion in 'General Aquaponics discussion - Aquaponics system ' started by mwestvang, Apr 20, 2013.

  1. mwestvang

    mwestvang Member

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    I'm new too the forum but have enjoyed reading a bunch of threads. I have a 300 gallon system with a 200 gallon fish tank (IBC) and a 100 gallon sump. We've been running for 5 weeks now and have seen the Ammonium and Nitrite levels spike and go to near zero. Nitrates are running at 40 now. My problem is that my PH is running about 8.4 consistantly and the plants in the beds seem too have stopped growing and are starting to get yellow edges on the leaves.

    I've read that the PH will come down on it's own as the system matures but what do I do for the plants now?

    Mike
     
  2. Yabbies4me

    Yabbies4me Administrator Staff Member

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    Hi Mike, welcome!

    Add Chelated Iron at one heaped teaspoon per 1000L of water, about every 4-6 weeks...

    ...and treat any top-up water with Hydrchloric acid to a pH in the low 6's the day before adding to the main system, this will consume any carbonates in the top-up water before it's added to the main system, which in turn will enable the natural acids produced by the nitrification process to consume the carbonates in the main system sooner, so the pH of your system will begin to drop sooner.

    When adding the acid treated top-up water to the main system it should be done in stages over a few hours, so as not to bounce the pH in the main system too dramatically.
     
  3. mwestvang

    mwestvang Member

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    Great! I just found Iron Chelate at our local feed and seed store. I'll add some of that today.

    I'm going to do a PH check on my well water today also to see what my sorce water is.

    Mike
     
  4. mwestvang

    mwestvang Member

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    I'm using expanded shale as our medium in the beds. Some say that it's will cause the PH to be high. Do you have any thoughts on Expanded Shale as a medium?

    Mike
     
  5. mwestvang

    mwestvang Member

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    Well I think I found the culprit. My well water used for top off is running 7.8 ph or more. I need to run a high PH test tomorrow when my son gets home. So it looks like we will need to treat our top water. I add about 5 gallons of water per day and my FT ph this morning was 8.3, what ph can I set the top water safely?

    Mike
     
  6. benwalters

    benwalters Member

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    gday mike,
    To test if your medium is contributing to high ph, get a glass with vinegar in it , put expanded shale in , check to see if small bubbles are produced
    The acid from the vinegar should produce a reaction, if there is any lime in your medium, so im led to believe
    good luck with it,
    cheers
    ben
     
  7. stevens

    stevens New Member

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    hallo,my tank 1600*400! how many litres? running a ph 7.00 how do i bring it down? how many barramundy can I put into tank?at what ph happy fishing steve Darwin.
     
  8. benwalters

    benwalters Member

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    Hi steve, you could have started a new thread, but heres my 2c
    320 litres, ph 7 is perfect, i think barra eat each other so you could put 20 little ones in (guesstimate)
    pics are always good,
    cheers
    ben
     
  9. Yabbies4me

    Yabbies4me Administrator Staff Member

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    ...
    Hi Steve, welcome to the forum.

    Fish stocking rates are determined by the amount of bio-filtration (gravel in aquaponics) you have in place, not the amount of water you have in the system. There is a gravel:water ratio that needs to be loosely adhered to as well, but the gravel:fish ratio is the most important.


    So until you tell us how much gravel you have in the system we can’t really give you a figure on how many fish you could safely stock, but you can work it out from the following info:

    Gravel:Fish ratio

    Ideally you want 25-30L of wet gravel per fish in a new system, or 20L+ of gravel per fish in a well established system. Don't include the 25-50mm of dry gravel at the top of the grow bed (GB) in your calc's, this is especially important in shallow beds under the recommended 300mm depth.

    Gravel:Water ratio

    Once you have figured out your gravel:fish ratio and determined how many fish you can safely stock, you can then figure out your optimum water capacity.


    Ideally the gravel:water ratio should be somewhere between 1:1 and 2:1, most backyard AP'ers run systems around 1:1 because of space constraints, as 2:1 requires twice the amount of gravel, so twice the m² surface area of GB's.

    While 2:1 is regarded as optimum, a ratio of 1:1 is run very successfully by many AP'ers, in fact some successfully run systems with gravel:water ratios as low as 0.6:1... ie: 600L of gravel to 1000L of water, but that is getting towards the lower end of the successful scale IMO, any lower starts to affect plant health/growth.

    If already have your FT and GB in place and operating and you find it doesn't fit into the parameters above, then they can be adjusted, ie: by adding extra GB's, as long as you fall within the following ratios:

    Gravel:Fish... 25-30L:1 (new system), or 20L+:1 (well established system)
    Gravel:Water... 0.6:1 - 2:1

    Optimum GB depth has been determined to be 300mm, going deeper, ie: running 600mm deep gravel in your GB's, will enable you to say take your gravel:water ratio from 1:1 to 2:1 in the same area, but won't necessarily enable you to run more fish, even though you now have more gravel, this is because your GB m² surface area will still be the same so you can't grow the extra plants required to remove the extra nitrates from the water. Plus it would make your GB’s incredibly heavy when filled with 600mm of gravel and water.


    GB’s shallower than 300mm will mean you will need far more m² area to get the amount of gravel required for your fish numbers. Plus, shallower GB’s also transfer cold/heat to the water more readily.

    Clear as mud?...

    A pH of 7.0 is fine, don't touch it, the bacteria will develop better if the pH is high. Once the system is cycled the natural acids produced by the nitrification process will begin to drop the pH, when it gets to about 6.6-6.7 you'll be wanting to add lime or Potassium bicarbonate to keep the pH from dropping any further.

    Cheers.
     
    Last edited: Apr 22, 2013
  10. Yabbies4me

    Yabbies4me Administrator Staff Member

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    Also, as Ben mentioned, probably a good idea to start your own intro thread, tell us about your system and maybe include some photo's... this'll help us to help you if the need arises.

    Cheers.
     
  11. mwestvang

    mwestvang Member

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    Thanks! the expanded shale is bubbling in the vinagar. Does this mean we need to change out our media?

    Mike
     
  12. Yabbies4me

    Yabbies4me Administrator Staff Member

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    If it contains carbonates there will be streams of very fine bubbles constantly rising from the gravel.

    If it was just a few larger bubbles when you first dropped it in that's okay.
     
  13. stevens

    stevens New Member

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    thanks, only have one GB 1100*350 established will add another bed.barra here 100ml long 2.20each,don't no as yet how to add foto?steve.
     
  14. benwalters

    benwalters Member

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    steve, above the text box you are typing in are tools such as font, size , smillie, then there is too more to the right, than is a little picture-frame button, press that and follow instruction and it will upload photos, cheers ,ben
     
  15. benwalters

    benwalters Member

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    hi mike the shale sounds dodgy, might have to get rid of it ,
    good luck
    ben
     
  16. mwestvang

    mwestvang Member

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    Ben,

    That's what I'm thinking too. We tested a handfull in a glass jar and had multiple fine streams of bubbles.

    Mike
     
  17. mwestvang

    mwestvang Member

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    I'm taking my glass jar and vinagar to the soil and rock place today and testing media. Hope to find something that is ph neutral.
    Now with the bacteria well established in the current beds how do I change media without loosing my system cycle?

    Mike
     
  18. stevens

    stevens New Member

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    ben,thanks the photo of fish tank is in my phone ,will not download to photo gallery so i can post a reply,was there a price/.place to buy barra?steve
     
  19. mwestvang

    mwestvang Member

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    We built a peat tea filter and run it 24/7. It took the 8.4+ water and outputs it at 7.6. We've been able to get the overall ph down to about 8.0 now. Going to reengineer the tea bag filter today but it looks to be working.

    Talking with AP folks here in Texas it looks like the expanded shale will settle out in a couple of months and be fine.

    In the mean time we will continue to monitor and treat.

    Mike
     
  20. andyholloway

    andyholloway Super Moderator

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