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Thread: CO2 regulator pressure behaviour

  1. #1

    CO2 regulator pressure behaviour

    Hi,

    I have a Dennerle CO2 regulator with double manometers.

    Each time I open my needle valve, the service pressure drops. If I close the needle valve, the working pressure increases. Thus, adjusting bubble count is very hard since working pressure variations significantely affect the bubble count (the higher the working pressure, the faster is the bubblle count). So, to increase my bubble count, I need each time to open the needle valve and than readjust the working pressure.

    Is my regulator behaviour normal or is it a bad manufactured product. I thought working pressure should be fixed with its own dedicated valve and not being affected by distal pressure variations

    Many thanks to clear this for me
    Aquatic Natur Cocoon 7: 11gal, dry start success / low light / CO2
    >>Follow it here<<

    Aquatlantis Evasion 120: Stopped ---> Malawi setup = No Plants

  2. #2
    Most in the USA tend to use a few cheap brands, or we get a really nice welding supply CO2 regulator.

    Even with some of the cheaper brands, I've not seen much drop.

    By adjusting the outlet pressure, typically in the 15psi range(I rarely use the metric equilvalent), this should be ample pressure that should remain stable. some brands have only a pre set out let pressure, others such as dual gauge give you gas tank pressure(800-1000psi), and outlet pressure(adjustable, 0-60psi or so, with most using 10-20psi ranges).

    Yes, if the outlet pressure was too low, it would make adjustments very hard!
    Might be defective?

    I have not used the brand as it's rare in the USA, more a European brand.
    I like Victor Regulators for CO2, they have been running for 20 years without any issues.

    If you set the outlet pressure at say 2-4psi, then you'd have the issues you sound like you are having. If you set the outlet pressure at say 15-20psi, there should be no affect on adjusting the bubble rate, even at very high CO2 flow rates or bubble/second.

    Regards,
    Tom Barr

  3. #3
    Thanks Tom for the feedback

    I'm getting concerned now. I have to set my working pressure to 2 bars (30 Psi) to get any CO2 flow. I also noted that my Solenoid has its green LED dead, but it still works. Yet, even a slight move on the needle valve will result in a significant variation of the working pressure.

    Does it mean a damaged regulator? Bad news in that case as they are rather expensive in Europe
    Aquatic Natur Cocoon 7: 11gal, dry start success / low light / CO2
    >>Follow it here<<

    Aquatlantis Evasion 120: Stopped ---> Malawi setup = No Plants

  4. #4
    Feedback and conclusions:

    I changed my canister today from a 2Kg to a 7.5Kg CO2.

    I installed a new Tunze 7077/2 regulator: no more problems with the working pressure changing when I turn the needle valve. Also, made a leak test by turning off the canister main valve and shutting down solenoid. I saw that pressure rapidely drops with my Dennerle Regulator despite no leak on all circuit identified. I finally figured out that it was leaking from the needle valve screw The more I open the needle valve, the more it was leaking. With the Tunze regulator, no problem. My Regulator was bad cheap quality despite the price. It is the last time I buy sometjing from an Aquarium Specific brand. Better go with technical/industrial cheaper/better quality equippement



    I also decided to stop the hassle with those end of life canister pressure rebounds.
    A simpel test to see if the regulator can handle a stable working pressure at the end of life of canister is as follow:

    Shut off main canister valve. Keep solenoid and all other valves open as in your setup. Canister pressure will rapidely drop and you can monitor the working pressure on the regulator gauge. If it increases before dropping, it means the regulator won't handle end of life of canister --> CO2 increase that can be dangerous to your fish
    Sadely, even the Tunze didn't pass that test, despite being followed by the unique 51-1-12 Ideal needle valve

    I made much research and finally found that you will need a 2-stage regulator to have a constant working pressure even when canister pressure is dropping. I also found this one:

    pressure regulators

    Simple stage regulators with a pressure compensation claiming for 2-stage regulator performance while keeping with a less than 50 USD price. They also have 2-stage regulators, all available in Germany for Europe: gasetechnik24.de - Ihr Partner für Druckminderer und zentrale Gaseversorgung


    I'll give them a try soon, and will add a 51-1-12 valve to them
    Aquatic Natur Cocoon 7: 11gal, dry start success / low light / CO2
    >>Follow it here<<

    Aquatlantis Evasion 120: Stopped ---> Malawi setup = No Plants

  5. #5
    Join Date
    Sep 2005
    Location
    Burlington, NC
    Posts
    2,510
    You will really like the two stage regulators with Ideal valves.
    Last edited by Left C; 09-22-2009 at 09:01 PM.

  6. #6
    My kingdom for a nice CO2 solution

    A good regulator is well worth the effort, same for a needle valve and solenoid.

    From there, we can move downstream to a good bubble counter, check valve and then finally to CO2 diffusion.

    Each point is critical.

    Once in the water, CO2 needs measured somehow or careful eyeballing(fish, plants, algae etc). Riccia seems to do well attached to stones.

    Pearls well 1/2 way through the day when CO2 is good. If not, not enough CO2.

    If plants are happy, no algae, fish fine, then do not add more.

    We can easily mitigate CO2 stress several ways and have much more effective management:

    1. Good flow, not enough to break the water's surface but a little less that that is a good rule of green thumb.
    2. Good quality CO2 equipment and Gas tanks, needle valve.
    3. Effective measurement(harder)- relative measurement once you know what to look for.
    4. Less light= less CO2 demand from plants
    5. Good filter, routine cleaning, water changes often=> less organic decomposition and O2 draw
    6. Reasonable long term fish load(not overstocking)
    7. Smaller fish= less O2 than larger say Discus etc requirements(the answer why is obvious, think about it- do not answer PKM! Let them think about it))
    8. Good dosing, good feeding of fish
    9. Riccia rock, about 1/2 way through the day, the riccia stone will start to pearl well(biotest). This suggest good CO2.
    10. Watch the tank, respect CO2, adjust methodically and carefully.

    Not quite as simple as it seems.
    Sadly, many give it a passing fancy at best.
    Guess they know it all with respect to CO2?
    Must be nice.


    Regards,
    Tom Barr

  7. #7
    Many thanks Tom for that sum-it up

    Actually, thanks to the advices I received here, I moved to low light, and it made a big difference. I have no algae except stable BBA on only one wood that I don't touch as it is self limited and adds some nice look to my wood.

    Arriving at the end of the canister made my life a nightmare for 3 weeks with a 2Kg canister (CO2 spikes because of working pressure increases when canister pressure drops). Now, I moved to an industrial 7.5Kg canister that will last me a while. If I kept my actual regulator, I'll have to deal with 2 months of pressure fluctuations when the canister will run out

    So, investing in a good regulator, needle valve and swagelok adapters is definite +

    Also, I posted the ways to test the regulator for "end of life of canister behavior" and to look for leaks with the pressure drop test when solenoid is off and canister shut-off, as they could help people decide
    Aquatic Natur Cocoon 7: 11gal, dry start success / low light / CO2
    >>Follow it here<<

    Aquatlantis Evasion 120: Stopped ---> Malawi setup = No Plants

  8. #8
    Quote Originally Posted by jonny_ftm View Post
    Feedback and conclusions:

    I changed my canister today from a 2Kg to a 7.5Kg CO2.

    I installed a new Tunze 7077/2 regulator: no more problems with the working pressure changing when I turn the needle valve. Also, made a leak test by turning off the canister main valve and shutting down solenoid. I saw that pressure rapidely drops with my Dennerle Regulator despite no leak on all circuit identified. I finally figured out that it was leaking from the needle valve screw The more I open the needle valve, the more it was leaking. With the Tunze regulator, no problem. My Regulator was bad cheap quality despite the price. It is the last time I buy sometjing from an Aquarium Specific brand. Better go with technical/industrial cheaper/better quality equippement



    I also decided to stop the hassle with those end of life canister pressure rebounds.
    A simpel test to see if the regulator can handle a stable working pressure at the end of life of canister is as follow:

    Shut off main canister valve. Keep solenoid and all other valves open as in your setup. Canister pressure will rapidely drop and you can monitor the working pressure on the regulator gauge. If it increases before dropping, it means the regulator won't handle end of life of canister --> CO2 increase that can be dangerous to your fish

    Sadely, even the Tunze didn't pass that test, despite being followed by the unique 51-1-12 Ideal needle valve

    I made much research and finally found that you will need a 2-stage regulator to have a constant working pressure even when canister pressure is dropping. I also found this one:

    pressure regulators

    Simple stage regulators with a pressure compensation claiming for 2-stage regulator performance while keeping with a less than 50 USD price. They also have 2-stage regulators, all available in Germany for Europe: gasetechnik24.de - Ihr Partner für Druckminderer und zentrale Gaseversorgung


    I'll give them a try soon, and will add a 51-1-12 valve to them
    My Azoo didn't pass the test too. I had checked for a used 2-stage Victor
    but the shipping cost killed the deal ($56.95), quite heavy.

    Only if there was something like an accessory to add the lacked function
    of a single-stage regulator...

  9. #9
    Yes, there is way around the single stage reg's, tell folks not to buy them and hopefully the aquarium companies wills top selling cheapo reg's

    Regards,
    Tom Barr

  10. Hi everyone

    i missed a very nice conversation and i'm facing a problem with my co2 rate.
    i am using a cheap regulator made in china, in my 55g tank the bubble was unstable i had to check it for every couple of hours

    when i moved the regulator to my 25g tank the bubble rate is now stable.
    i bought a better regulator later on, and when i used it on my 55g tank it happenned again, the bubble became unstable.

    please help

    is it related to pressure balance between my diffuser and my bubble counter??

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