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Thread: DOS not dosing expected amount of Alk

  1. #1
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    DOS not dosing expected amount of Alk

    I currently have my DOS programmed to dose 25ml of Alk but only 20.5ml showing in Fusion. The first day showed 25ml and last two days 20.5ml.
    Calcium is currently switched off.

    Can anyone advise what is causing this.

    Many thanks

    Screen Shot 2017-05-28 at 18.04.44.png

    Screen Shot 2017-05-28 at 18.05.01.png

  2. #2
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    Thought I'd resolved this problem by updating the 1Link module and rebooting but only read correctly one day now reporting varying degrees of amounts dosed. Strange as my Calcium dose which is now back is reading correctly.
    Any ways to resolve this would be appreciated

  3. #3
    Master Control Freak RussM's Avatar
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    Do you have a high pH shutoff programmed for the Alk pump?
    Please do not send me PMs with technical questions or requesting assistance - use the forums for Apex help. PM me ONLY if the matter is of a private or personal nature. Thanks.

  4. #4
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    Hi Russ Yes I do and I think you have got the answer. If it hits that level will the DOS stop dosing at that point and record only what it has dosed to that point?

  5. #5
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    On my charts it does show it reaching the shut off pH but thinking about it does show it has reached that level briefly on the display and I have had email alarms for that. It very soon drops again to below the level.

    Looked at the output log and seems to confirm that it is switching on and off during the dosing.

    Screen Shot 2017-06-04 at 18.08.29.png

  6. #6
    Master Control Freak RussM's Avatar
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    I suggest that you spread out the Alk dosing over a much longer period of time. Calcium too.
    Please do not send me PMs with technical questions or requesting assistance - use the forums for Apex help. PM me ONLY if the matter is of a private or personal nature. Thanks.

  7. #7
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    Ok will try that but also temporily raise my cut off Ph level to see if that works

  8. #8
    Master Control Freak RussM's Avatar
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    The placement of the pH probe and Alk output tubing may also be a factor - if they are close together and both in an area of low flow, the Alk being added does not get diluted quickly enough, and you end up with a localized area of higher pH. But speaking out the dosing over a longer period of time will mitigate that.

    I moved this thread to the DOS forum, as it really isn't about Fusion. I'll also rename it more descriptively.
    Please do not send me PMs with technical questions or requesting assistance - use the forums for Apex help. PM me ONLY if the matter is of a private or personal nature. Thanks.

  9. #9
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    The probe and the dosing are within a few inches of each other in the sump. Although the dosing is near the intake on the return pump I think you are right about it not getting diluted quick enough and causing the spike in PH level.
    I temporarily raised the PH shut off level for today's dose and it is now showing the full dose so that clearly was the problem.
    I'll take your advise and spread the dose out over a longer period to help with the quicker dilution
    Thanks for your help.

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