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Thread: Programming daily fluctuations

  1. #1
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    Programming daily fluctuations

    I'm very new at this so I'd appreciate any feedback on the program below. My goal is to create daily temperature fluctuations in the tank to mimic what is happening in the wild (I want the ability to be able to input temperatures every hour; the room is maintained cool enough that no chillers are needed to decrease water temps). The approach I've come up with is to create 24 (!) virtual outlets, each on for an hour a day. Does this make sense? Any suggestions?


    VIRTOUT_01
    If Time 00:00 to 01:00 Then ON


    VIRTOUT_02
    If Time 01:00 to 02:00 Then ON


    ... and so on to VIRTOUT_24


    then for HEATER_I4 (real heater outlet)


    Fallback OFF
    Set OFF
    If VirtOutlet1 = ON Then ON
    If Temp < 21.5 Then ON
    If Temp > 22.5 Then OFF
    If VirtOutlet2 = ON Then ON
    If Temp < 22.5 Then ON
    If Temp > 23.5 Then OFF
    ...
    If VirtOutlet24 = ON Then ON
    If Temp < 21.5 Then ON
    If Temp > 22.5 Then OFF

  2. #2
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    You need to do this kind of logic, though I don't suggest doing so many points. Once you hit over about 100 outlets the apex stops playing nice. 4 or 8 is more than enough to pull off what you want (I'm showing 4)

    VO1 (0 to 6)
    If Temp XX Then ON
    If Temp YY Then OFF
    If Time 06:00 to 23:59 Then OFF

    VO2 (6 to 12)
    If Temp XX Then ON
    If Temp YY Then OFF
    If Time 12:00 to 05:59 Then OFF

    VO3 (12 to 18)
    If Temp XX Then ON
    If Temp YY Then OFF
    If Time 18:00 to 11:59 Then OFF

    VO4 (18 to 0)
    If Temp XX Then ON
    If Temp YY Then OFF
    If Time 00:00 to 17:59 Then OFF

    Heater
    Set OFF
    If Outlet VO1 = ON Then ON
    If Outlet VO2 = ON Then ON
    If Outlet VO3 = ON Then ON
    If Outlet VO4 = ON Then ON

    Sent from my SM-G935V using Tapatalk

  3. #3
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    Thanks, zombie. That's sort of what I ended up doing after some trial-and-error. Each of my VOs does this:

    Set OFF
    If Time 00:00 to 01:00 Then ON
    If Tmp > 22.3 Then OFF
    If Time 01:00 to 00:00 Then OFF

    and the Heater looks exactly the same as yours. I've created 24 VOs and it seems to run fine.

  4. #4
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    I would suggest some hysteresis on those so you don't wear out the outlet and/or the heater from the constant switching. For the example above I would do

    If Tmp < 22.2 Then ON
    If Tmp > 22.3 Then OFF
    If Time 01:00 to 00:00 Then OFF

    That should cut the switching in about a third but still maintain a very consistent temp.

    Sent from my SM-G935V using Tapatalk

  5. #5
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    Thanks! I'll make the changes.

  6. #6
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    Is there really much temperature change in the ocean during the course of the day? Sure at the surface there will be some change but once ou are down 10 feet or so I don't see an hourly let alone daily change in temperature. Most of the fish and corals we deal with would be in stable temps I believe.

  7. #7
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    Quote Originally Posted by Frogfish View Post
    Is there really much temperature change in the ocean during the course of the day? Sure at the surface there will be some change but once ou are down 10 feet or so I don't see an hourly let alone daily change in temperature. Most of the fish and corals we deal with would be in stable temps I believe.
    From my research a while back I believe that variations of 1-2 degrees are common at 30 foot depths.

    The secondary but probably more important reason to do something like this (I personally do a simplified version of this that changes every 6 hours) is to improve the stress tolerance of corals. Regular changes in temperature within reasonable limits have shown to increase the survivability of corals during emergency situations such as failing heaters power outages, etc. With that said, consistent temps do improve coral growth, so it becomes kind of a balancing act between stress tolerance and growth potential as to the level of daily fluctuation if you choose to do so at all.

    Sent from my SM-G935V using Tapatalk

  8. #8
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    @Frogfish We use Apexes in our research lab. We study fish responses to temperature variation and have many large tanks in which we grow minnows (in individual containers). You're right that water at depth varies a little bit throughout the day, but these minnows live in shallow ponds or rivers that really warm up in the early afternoon.

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