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Thread: Relationship between ORP readings and feeding the tank

  1. #1
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    Relationship between ORP readings and feeding the tank

    I recently saw the clips on MACNAMARA by mr saltwater tank and during the neptune segment, it was mentioned that if the orp reading is low, then we should somehow stop feeding the tantank

    my question is what constitute a low reading and what is a normal reading range?

  2. #2
    Relax stoked! chris_kitedude's Avatar
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    some reading material : http://www.reefkeeping.com/issues/2003-12/rhf/feature/

    fw and sw readings in the range between 200 and 450mv are common. in basic : the higher the cleaner the lower the dirtiert the water - well like all things in our small aquarium world this things can be higly debateable. the best thing is and always be your own eye as a meter how your animals in your tank behave.

    regards
    c
    C​hris

  3. #3
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    The idea behind what you heard me say on that video is that sometimes negative things can happen in your tank that can bring down your water quality (spawning, fish die off, someone manually overfeeding, etc.). At times these things will lower your ORP below what YOU may deem normal for YOUR tank. So, if this was happening, you would not want to further pollute your tank with an automatic feeding until you know what was causing it or until the water had cleared up.

  4. #4
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    Terence

    then what reading would constitute poor water quality in your opinion?

    if I am going to program the apex to stop feeding if the orp drop a certain level, what would the recommended level be? I still have not gotten a clear answer yet

  5. #5
    Master Control Freak RussM's Avatar
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    You won't find a clear answer. You need to make a judgement call after observing the normal trends of ORP for your tank while the tank is running under what you deem to be good conditions.

    A heavily fed heavily fish-stocked system is going to have a difference range of "normal" than a SPS-dominate tank with few fish. Whether or not you dose ozone is a big factor. Even the particular salt used can affect it. I saw a noticeable change in the average ORP reading when I switched from RSCP salt mix to NSW, for example.

    450-475 seems to be the most commonly touted high level value, but the low end value is widely debated, it seems to me.
    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.

  6. #6
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    As Terence and Russ mentioned, there really is no correct answer that works for everyone. Once your ORP probe breaks in (it can take a week or two) and starts measuring consistant readings, you'll find the ORP rises and falls during the day. After a bit, you'll finally be able to figure out the "normal" for your tank. For me, it varies between 340 and 370. When I do a water change, it'll drop to the low 300s. So for me, I set a warning/alert for anything below 250.

  7. #7
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    Mine's at 460, Should I feed the tank more to lower it? I just did a water change and nothing changed ORP wise...

  8. #8
    Frequent Contributor zombie's Avatar
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    Quote Originally Posted by Schmitty View Post
    Mine's at 460, Should I feed the tank more to lower it? I just did a water change and nothing changed ORP wise...
    No. Chasing particular ORP values will make you go crazy and will cause more harm than good. The ORP probes calibration procedure is complicated and expensive so you don't even know for sure if the ORP value you have is dead on to begin with. If your tank is healthy (very low but measurable phosphates and nitrates and nitrite and ammonia always 0, fish and corals growing) then you can be reasonably sure your typical ORP range is reasonable and you don't need to make adjustments to feeding because of it.

    You might be an engineer if...You have no life and can prove it mathematically.

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