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What is the right ph level for fish

Discussion in 'Gardening Discussion - Other gardening systems.' started by peter lica, Feb 7, 2016.

  1. peter lica

    peter lica Member

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    Hey guys
    Just set up a aquaponics system what is the right ph level for my fish

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  2. Yabbies4me

    Yabbies4me Administrator Staff Member

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    Hey Peter,

    Most fish, including those commonly used in aquaponics in Aust, prefer a slightly alkaline pH, ie: 7.0-8.0

    Most scheme and bore water in WA, especially in coastal areas, is alkaline. For example, here in Perth the water in most areas comes out of the tap with a pH in the high 7's, but within a day or two, once the Chlorine has evaporated out, the pH has usually risen to up around 8.2-8.4. This pH is fine for the fish, but will be locking out Iron and possibly Zinc for the plants. The majority of plants prefer a pH in the low 6's, but deficiencies don't start becoming an issue until the pH is in the high 7's.

    Most AP'ers aim for a system pH of around 6.7-6.8, as this creates a happy medium in regards to both plants and fish. However if your system pH starts out high due to the source water, don't be in a rush to reduce it, it will drop naturally on it's own, at which point you will be having to constantly add Calcium hydroxide and Potassium bicarbonate to raise and buffer the pH.
     
  3. peter lica

    peter lica Member

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    My ph level at the moment is 8.2 should i lower it to around 6

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  4. Terra

    Terra Active Member

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    Test your top up water if its really high you may need to treat it to reduce ph before adding if your ph becomes a long term problem

    Rain water is usually around 6ph so top ups with that will help a bit

    As yabbies wrote it will come down as your system ages , so best bet is just wait , foliar spray your plants with iron ( its locked out at high ph)
     
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  5. peter lica

    peter lica Member

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    How often do you use the foliar spray

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  6. Terra

    Terra Active Member

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    As with every thing aquaponic it depends

    Try two to three week intervals and see how you go
     
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  7. peter lica

    peter lica Member

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    Thanks mate

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  8. Yabbies4me

    Yabbies4me Administrator Staff Member

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    Iron will start being locked out at a pH above 7.5 but doesn't normally become an issue until the pH reaches 8.0+

    Foliar feeding Iron may help, but I've found that adding chelated Iron to the system is extremely effective in reversing Iron Chlorosis caused by high pH... However, not all chelated Irons are created equal...

    The Yates chelated Iron commonly found in garden centres and the big 'B' store etc, is EDTA Chelated Iron, which is not available to the plants at the high pH's being discussed here. You want EDDHA chelated Iron, it is available to the plants across a wide pH range, some reports suggesting up to a pH of 11.0

    Don't over do it with the Iron, plants can have too much. I've used this EDDHA Iron at about a 1/4 of a teaspoon into the 500L IBC system in the shop and seen Iron chlorosis reversed in two days... and even that little amount gave the water a red tinge.

    Cheers!
     
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  9. peter lica

    peter lica Member

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    Thanks is this available at bunnings?

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  10. Yabbies4me

    Yabbies4me Administrator Staff Member

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    Not EDDHA. I've only seen the Yates and Manutech chelated Irons at Bunnings, which are both EDTA, whish is only available to plants at a pH up to 6.5 supposedly.
     
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  11. Ringer

    Ringer Active Member

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    Hi yabbies
    Can you recommend a brand of chelated iron I can try and where to get it ? I've not needed it before but I'm sure it's just a matter of time till I do.
    Cheers
     
  12. Murray

    Murray Site Admin Staff Member

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    I have some bulk iron here. Not packed it off ready for sale as yet. Will have to get on with it.
     
  13. Yabbies4me

    Yabbies4me Administrator Staff Member

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    There is a link for EDDHA Iron in my earlier post that you quoted Ringer, but you're just around the corner from Murray, so I'd be seeing what he's got there first.

    If you want chelated Iron because of high pH locking out Iron in your system (ie: 7.5+), then you'll need EDDHA Iron, but use it sparingly. It doesn't take very much chelated Iron to correct Iron chlorosis and too much EDDHA will turn your water dark red. I've fixed Iron chlorosis within 3 days using only 1/4 level teaspoon per 1000L. At 1/2 a level tspn per 1000L your water will have a definite pink tinge, and at 1x level tspn per 1000L (a commonly recommended rate on forums), your water will turn dark red.

    I never thought this was the case... until I recently did away with the "teaspoon" I'd been using and bought a proper set of measuring spoons, then I found out I'd be under dosing by nearly half. I then tried the 1x "proper" level teaspoon in 1000L rate, and it definitely turned the water red. A common complaint is that people can't even see their fish at that rate, but I could still see the fish at the bottom of 500l of water in an IBC type tank.

    If your pH is below 7.0 and the Iron chlorosis issue is simply due to an overall lack of Iron in the system, then you could still use EDDHA (of all the Iron chelates, it's available to plants across the widest pH spectrum), but DTPA will also do the job.

    DTPA supposedly starts to become less effective once the pH is over 7.0, and completely ineffective at a pH of 7.5 and above. However, it will not turn your water red, which is why it's recommended on forums etc for Iron deficiency issues in systems with a pH of 7.0 or lower.
     

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