This site is supported by the advertisements on it, please disable your AdBlocker so we can continue to provide you with the quality content you expect.
  1. We are after as many aquarium plant images that we can get, doing so will assist us in completing the aquarium plant database.

    https://barrreport.com/threads/aquatic-plant-images-wanted.14374/
    Dismiss Notice

A different method to measure CO2 at VERY high bubble rates

Discussion in 'CO2 Enrichment' started by Tom Barr, Jan 31, 2013.

  1. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,694
    Likes Received:
    728
    Local Time:
    10:54 AM
    Frankly, I've never used bubble rates too much, just a rough gauge, an estimation. Then I spend a fair amount of time dialing in the correct rate for that tank. I do not like having to do that process again and again, anytime I switch out CO2 equipment.
    I loath that chore.

    Someone, a client, asked me how to adjust high rates a few years back. I said using a few different bubble counters etc.
    He came back with a 1200$ programmable mass gas flow controller. Okay that works nice, but it's 1200$.

    Just to measure CO2.

    I found a big leak in my solenoid(clippard), so I needed to remove it, and I'd just gotten a couple of nice dual stage CO2 reg builds from Oldpunk.
    So the problem is how to set the bubble rates exactly like the old set up regulator?? Yes, I could have just removed the solenoids, but I have these nice pretty Dual regs, and well, wanted to switch them out anyway. 10-20 years is enough service for the old Victor single stages. Maybe I'll sell them, err, without the leaky solenoid!

    The solution is deceptively simple and it works quite well.

    I used a 2 liter flask and inverted it in the aquarium, then took the CO2 line from the old reg, and got a feel for the general bubble flow rate, then dialed the new Dual stage reg to about the same bubble rate.
    I used the stop watch on my iPhone to measure time, then measured the old reg vs the new reg's fill rate to 500mls(this took about 4 minutes). My 1st attempt was lucky, I got to within 30mls, I adjusted the CO2 up a tad(1 click/notch) and I put the new regulator back on.

    So the old reg: 500mls in 239 seconds
    The New reg: 500mls in 249 seconds

    Not bad, and a better method that bubbles per second which is impractical for larger tanks. This method addresses variations in bubble sizes and tubing size differences also, so it's a much better simple method to measure the RATE of CO2.
    Once you get it close, then you can tweak a little each few days and observe.

    You do not need to use some $$ glassware, a large container will do where you can view the gas inside, and then make a mark at say the 2-5 min point. Then try and match that flow rate with the new regulator.
    You can also estimate based on the time you have the CO2 gas "on" and how much CO2 gas volume is in the tank, pretty close how long the gas tank will last, before running out.

    ml/min of CO2 is a better unit than bubbles per second, much like PAR vs Watts/gallon.
    This is a better comparative measure for CO2. Yes, you can use the pH/KH "relative" measure also, and likely should use that in conjunction.
     
  2. puopg

    puopg Guru Class Expert

    Joined:
    Nov 19, 2012
    Messages:
    214
    Likes Received:
    0
    Local Time:
    10:54 AM
    Pretty great idea! Do we first need to know our required CO2 level first? Meaning, we have to first have dialed in CO2 to the point we are seeing good results, little algae, etc. Then since we now have a good level, we measure the rate of flow using the inverted flask method? THen we save this and when a new regulator gets installed, we have a point of reference to match.
     
  3. kevmo911

    kevmo911 Member

    Joined:
    Oct 19, 2010
    Messages:
    67
    Likes Received:
    0
    Local Time:
    10:54 AM
    This is so simple it's brilliant.

    The most popular bubble counter variety is clearly the JBJ-style, but many of us have switched over to the cheapo inline HK-special glass counters, which have a *much* smaller orifice. Where it might have been possible to count the bubbles in a JBJ for a decent-sized tank, it might be completely impossible to do so using the generic glass bc's. Instead of the "wait until your fish freak out" or "give it a few hours and hope you haven't suddenly become colorblind and that your 4dKH is actually 4dKH" methods of dialing in CO2, this is a great alternative.

    My point is that not only is this a useful technique for measuring high flow, it's also good for when your bubble counter orifice is small enough that you can only measure about 3 levels of flow - none, a little, and plenty.
     
  4. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,694
    Likes Received:
    728
    Local Time:
    10:54 AM
    Well, it's sort of like using bubbles per sec vs Volume of gas, the rate of gas will be constant regardless of the bubble sizes or your counting a whizzing bubble flying by.

    Or, like comparing watts/gal to PAR. And anyone can do it, including for small tanks, you just need a smaller container and use tick marks.

    This gives a pretty good bench mark with good light PAR data, far better than ADA's list of supposed CO2 which cannot be possible.
    And ADA does not give PAR data either.

    And if you do not have some stable comparative method for light and CO2, you really don't know Jack manure.
     
  5. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,694
    Likes Received:
    728
    Local Time:
    10:54 AM
    Yes, 90% of CO2 is relative based on the plants.

    But if something changes, you can always check with the gas collection method.
    So when things are doing well, measure the gas!!

    Now you have a reference.
     
  6. UDGags

    UDGags Lifetime Charter Member
    Lifetime Member

    Joined:
    Sep 13, 2009
    Messages:
    630
    Likes Received:
    37
    Local Time:
    10:54 AM
    I was curious which one of your tanks these measurements were done on (as a reference point)?

    Sent from my DROID BIONIC using Tapatalk 2
     
  7. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,694
    Likes Received:
    728
    Local Time:
    10:54 AM
    180 Gallon.

    About about 58 liters of CO2 per day.
    1734 liters a month.

    There are 231 liters of CO2 in 1 lb.
    So 10 lbs tank will last= 1.33 months, or about 5-6 weeks at this rate.
    20lbs will last a tad longer, about almost 3 months I'd say.

    I could likely improve this a good deal.

    CO2 has a molar weight of 44 grams.
    A pound is 454 grams, so you've got 10.3 moles.
    PV = nRT
    weight = mass * gravity
    1 ft^3 = 7.480519 gallons
    1 litre = 0.2641721 gallons

    At Standard Temp and Pressure, that's 231 litres, or nearly 61 gallons (US).

    Now this also gives you a reference of improving the CO2 delivery system by adding say a reactor post needle wheel, or adding a bean animal prefilter, or increasing decreasing the surface movement etc.
     
  8. UDGags

    UDGags Lifetime Charter Member
    Lifetime Member

    Joined:
    Sep 13, 2009
    Messages:
    630
    Likes Received:
    37
    Local Time:
    10:54 AM
    Thanks

    One could also put their CO2 tank on a scale and record weight loss over time to get the same numbers. I've done this with propane tanks for a flare system on a furnace. I'm guessing not many people have access to a higher end scale though in terms of precision and max weight.You use 113.5g per day or 14.19g per hour (assumed 8hrs of CO2) so a normal household scale probably would only work if you recorded weight in terms of weeks/months. Most people are probably even worse off since they have smaller tanks.
     
  9. Tom Barr

    Tom Barr Founder
    Staff Member Administrator

    Joined:
    Jan 23, 2005
    Messages:
    18,694
    Likes Received:
    728
    Local Time:
    10:54 AM
    Scales are good for estimating when you'll need a gas change, but tough for measuring the flow rate of CO2 per unit time in seconds/minutes etc.

    Mass flow controllers: Alicat:

    http://www.alicat.com/products/gas-flow/mass-flow-controllers/
     
Loading...

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice