Shutting off DIY CO2

Discussion in 'Carbon Dioxide (CO2)' started by paul.stopher, 7 Nov 2009.

  1. paul.stopher

    paul.stopher Newly Registered

    Messages:
    23
    Location:
    Surrey UK
    Has anybody tried fitting a solenoide switch to DIY CO2?
    Would it be possible to set up a T Joint in the tubing one end to the tank and the other to a solenoide valve. Then just run the valve timed in reverse ie. open and dumping the CO2 at lights off and Closed allowing the CO2 to go to the tank lights on? Also would a simple anti siphon valve be safe enough when the Valve is open to prevent emptying the tank?
    Anyone got any thoughts on this?
    Thanks
    Paul.
     
  2. LondonDragon

    LondonDragon Administrator Staff Member

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    Location:
    London
    I don't recommend it, the DIY bottles are not designed to hold a lot of pressure like for example the fire extinguishers, if you try and shut it off you run the risk of the bottle exploding and creating a mess, do this at your own risk.
     
  3. paul.stopher

    paul.stopher Newly Registered

    Messages:
    23
    Location:
    Surrey UK
    Ok. I understand this but if the solenoide valve is open then the CO2 escapes from the reactor. Surely you would only get a problem if the valve failed?
     
  4. LondonDragon

    LondonDragon Administrator Staff Member

    Messages:
    10,301
    Location:
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    What's the purpose of the solenoid if you are going to leave it always open? If you shut it you risk a messy tank cabinet or living room.
     
  5. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
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    Location:
    Chicago, USA
    MEMO TO PAUL.STOPHER FROM JOHN RAMBO:

    :woot: Don't do it. Don't do it. Let it go....

    Cheers,
     
  6. JamesC

    JamesC Member

    Messages:
    1,276
    Location:
    Bexley, Kent
    Yes I would think this should work fine and the anti siphon valve is a necessity. There should be enough back pressure in the tubing going to the tank to force all the CO2 out through the open solenoid valve. Then when valve is closed all the CO2 would then go up the tube to the tank.

    TBH I wouldn't go to all the expense of buying a solenoid valve as DIY CO2 isn't that great and it may take too long to get levels up again in the tank by lights on. All DIY CO2 tanks I know off work fine on 24 hours. But if you feel that your CO2 production is high and you have a solenoid valve then it might work well for you.

    James
     
  7. a1Matt

    a1Matt Member

    Messages:
    2,498
    Location:
    Bromley
    No, I used a pump.

    I used a DIY internal reactor powered by a small pump being fed by DIY CO2. I had the output of the reactor (the bottom of it) next to my filters input.

    By turning the pump on and off (via a timer) it effectively switched off the CO2. When the pump was off the CO2 just bubbled straight out the top of the reactor. When it was on CO2 infused water was distributed throughout the tank. The reactor had a venturi loop which made it very efficient. The design is on http://www.barrreport.com

    I used two bottles of yeast and tweaked the mix so that it lasted a month. I replaced one bottle every two weeks, so I had stable levels.

    The whole system worked a treat for me, I know it is different to your plan, but I figured it might give you some more ideas.
     
  8. paul.stopher

    paul.stopher Newly Registered

    Messages:
    23
    Location:
    Surrey UK
    Wow lots of differing opinions. Was just looking at possible ways of turning the CO2 off as I'm getting very high readings on my Aqua Medic CO2 test in the mornings. BRIGHT YELLOW!!! I am running the lights for 8hrs a day but this leaves a long period 5hrs plus from when i get up to lights on and then another few hrs to bring the CO2 down to a decent green colouring on the tester. Am now wondering if the tester is not reading right. As this is a large 400l tank and the DIY is only running at about 1 bubble every 2seconds.
     
  9. ceg4048

    ceg4048 Expert/Global Moderator Staff Member

    Messages:
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    Location:
    Chicago, USA
    I don't really think the opinions differ that much at all. Just about all agree that solenoid on DIY CO2 is not a good idea, not unless your pop bottles are constructed of cast iron. If you vent the CO2 to atmosphere overnight then your house will smell like a brewery because the yeast odors will also escape. If you trap the pressure overnight and if the bottle doesn't rupture then when the valve is opened you'll have a surge through the diffuser. A solenoid is not a regulator. It cannot control the output pressure.

    If you fish aren't suffering I don't see why you are concerned about a yellow dropchecker. This is actually a good thing, unless you are using tank water in your dropchecker, which is a bad thing (false reading). You can use a1Matt's idea, but on a 400L tank a DIY CO2 is difficult to get right. On that size tank I would worry a lot less about shutting off the CO2 and a lot more about keeping the levels stable.

    Cheers,
     
  10. a1Matt

    a1Matt Member

    Messages:
    2,498
    Location:
    Bromley
    :text-+1: for what Clive says.

    I wonder the same thing. I would be very surprised if 1 bubble every 2 seconds could produce too high a CO2 level in a 400l tank. In a tank that size having the CO2 on 24/7 is more likely to be helping to maintain good levels of CO2.

    I would focus on stability of CO2 and distribution throughout the tank. Although if your fish and plants are doing fine then I would say if it ain't broke don't try to fix it!
     

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