ORP probe stuck & O3 ran for 4+ days straight

Discussion in 'Water Chemistry' started by Otty, Nov 30, 2008.

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  1. Otty

    Otty Giant Squid

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    Well I was just wondering if any of you had a ORP probe stick low on you causing your O3 to run constantly. Once I noticed mine I took the probe out and calibrated it and it has been running fine since. Guess next probe will be lab grade and not a Pinpoint.

    I have a ACIII and was wondering if there was any code anyone has came up with to guard against this.

    I can tell by the graph that is started to fail between the 13th and 19th but I never noticed it. Will have to come up with some kind of code to keep this from happening again. With a Eclipse 1 Series generator made for a 7k gal to 25k gal pool it can cause some damage on the tank if not controlled.

    [​IMG]
     
    Last edited: Nov 30, 2008
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  3. sessionthree

    sessionthree Spaghetti Worm

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    Otty,

    I assume you have something like this to turn on the O3 when ORP gets too low:
    If ORP < 450 Then OZN ON

    Add something like this as well:
    If ORP < 400 Then ALM ON (set an alarm event so that you can be notified)
    If ORP < 380 Then OZN OFF (turn off OZN if ORP goes too low as the reading might be incorrect)

    Put your own ORP values in, I was just using those for illustration.
     
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  4. Otty

    Otty Giant Squid

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    The problem is that the probe never said the ORP got that high so the unit ran non stop for almost 4 days. As you can see from the graph it doesn't ever take the unit long to get ORP up to 390, so I really don't know how high it got. Once I calibrated the probe it started working fine. Getting a lab grade probe on order.
    This is the code I have:

    If ORPA < 390 Then OZ3 ON
    If ORPA > 391 Then OZ3 OFF
    Max Change 010 M Then OZ3 OFF
     
  5. sessionthree

    sessionthree Spaghetti Worm

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    I was just about to post to suggest the Max Change command.

    It's too bad there's not a command (that I know of) to limit how long to keep something on after it turns on. (You can use the max change command when "ON" but that just makes sure it stays on for the length of time you specify which wouldn't be what you want.)
     
  6. Otty

    Otty Giant Squid

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    I use the Max change just to make sure it doesn't bounce on and off. I will try and see if I can get some thing to work. Thanks for the reply.
     
  7. sessionthree

    sessionthree Spaghetti Worm

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    This is kind of a wild idea, but how about something like this:

    OSC 030/240 ON/OFF Then DUM ON // define a dummy timer and put it on a OSC cycle (30 min on and 4 hours off in this example)

    If ORPA < 390 Then OZ3 ON
    If ORPA > 391 Then OZ3 OFF
    Max Change 010 M Then OZ3 OFF
    If Timer DUM = OFF Then OZ3 OFF // turn OZ3 off if the DUM timer is off

    When the ORP probe reads low, it will wait until the OSC on cycle on the DUM timer to turn on the ozone. The on cycle will stay for 30 minutes (or whatever you define) and raise the orp. If the ORP probe keeps reading low because it's stuck, the OZ3 won't stay on because OSC cycle will turn off for 4 hours (or whatever you define).

    If your orp probe got stuck low with this program, the OZ3 would come on for 30 minutes every 4 hours (or whatever numbers you define). That's better than being on all the time.
     
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  9. sessionthree

    sessionthree Spaghetti Worm

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    Ok one other idea is to only adjust ORP for an hour once a day (as an example):

    If Time > 12:00 Then OZ3 ON
    If Time > 13:00 Then OZ3 OFF
    If ORPA < 390 Then OZ3 ON
    If ORPA > 391 Then OZ3 OFF
    Max Change 010 M Then OZ3 OFF

    That way your OZ3 is only allowed to come on between noon and 1pm every day.
     
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  10. inwall75

    inwall75 Giant Squid

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    wow.....that's scary. I'm glad you caught it.
     
  11. PharmrJohn

    PharmrJohn The Dude

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    I am clueless on this one. I have heard of O3. I know I can run it threw my skimmer. I can look up on my own what it is and what it does, but what were the consequences of this situation?
     
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  12. inwall75

    inwall75 Giant Squid

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    Ozone oxidizes whatever organics it touches. In addition to the normal organics, it will also nuke Tannins, phenols, microalgaes, etc. That's why tanks with ozone almost look like they don't have any water in them and the fish are flying.

    If the controller got stuck in the "on" position, then ORP could continue rising to dangerous levels. Too high of ORP is just as dangerous as too low of an ORP.

    Ozone and the Reef Aquarium, Part 1: Chemistry and Biochemistry

    Ozone and the Reef Aquarium, Part 2: Equipment and Safety

    Ozone and the Reef Aquarium, Part 3: Changes in a Reef Aquarium upon Initiating Ozone
     
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