Zoom's Article 5- The Caution of CO2

Discussion in 'Articles' started by Zoom, May 16, 2012.

  1. Zoom

    Zoom Retired Moderator

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    I was going to call this thread "CO2 for Dummies". But firstly I would be infringing on the "For Dummies" trademark, and secondly, I would then be saying CO2 is easy.

    CO2 fertilization is becoming more and more popular within the hobby. There seems to be a fair amount of suppliers starting to import the various items necessary for pressurized CO2, and we are starting to benefit from more competitive prices. I'm actually surprised at the amount of newer members who are starting out and already considering CO2 addition to their tanks.

    A small mishap this week, as well as some extensive discussions with other members over the past few weeks have led me to write this article: "The caution of CO2". With the upgrade I recently did on my main display tank, I had a "spare" regulator. I purchased a small diffuser for Nano tanks, and decided that I was ready to upgrade my Nano tank to include pressurized CO2. A stupid error when opening up the bottle resulted in a burst of CO2 to enter the tank. I didn't think much of it, and continued to set up. About an hour later when I went back to check on the CO2 addition to the tank (which was at a rate of 1 bubble per 3 seconds) I noticed that about 60% of my Endler's were dead, and the rest were gasping for air at the surface.

    I've slowly realized that CO2 should only be considered after extensive research yourself. If you do not know what you are doing, or getting yourself into, you will land up with problems. I trust this article will give you the small push to do your research before venturing out into the land of pressurized CO2.

    Pressurized CO2 is the addition of Carbon Dioxide gas into a planted tank. Gas in a pressurized container is (usually) passed through a regulator, a solenoid and a needle valve. Gas is added to the tank through a CO2 diffuser which is usually made of ceramic. CO2 is added at a rate of "x" amount of bubbles per second, which is monitored using a CO2 bubble counter. If you need further information on the hardware necessary, please see the following article: http://www.tropicalaquarium.co.za/showthread.php?8156-CO2-Regulator-Solenoid-Needle-Valve

    Biology in school classes taught me that the basic building block to all organisms is Carbon. I am sure that you have now deduced that the addition of Carbon Dioxide is beneficial to plants, which absorb CO2, use the Carbon molecule as a building block, and release O2. This process is a chemical process within the cells of the plant that only occurs during the daytime. (Thus you need good light). At night, the plant respires, (takes in O2, and released CO2).

    So let's start at the basics. When do you need to add CO2 to your tank? Whilst we can all agree that no 2 tanks are the same, I'm going to categorically state that not every planted tank needs pressurized CO2. You need to do your research, and determine yourself if and when you want to add pressurized CO2.

    Low tech planted tanks do not need CO2 addition. Low tech tanks are classified as tanks with low light, easy to grow plants, usually an inert substrate, and a simple fertilization strategy.

    Medium tech planted tanks do not need pressurized CO2 addition. Medium tech tanks are classified as tanks with better lighting, some more difficult to grow plants, usually a nutrient rich substrate, and a more complex fertilization strategy. Usually this tank will receive other forms of Carbon addition through products like Microbelift BioCarbon or Seachem's Excell.

    High tech planted tanks may need pressurized CO2 addition. These tanks usually have very difficult to grow plants, high lighting, a nutrient rich substrate, and a highly complex (almost daily addition) fertilization strategy. You will notice I said "may" need CO2 because I have seen a few high tech set ups running without pressurized CO2, however the tank did receive some form of carbon additive.

    You can read the following article to give you a wider understanding of the different levels of tanks: http://www.tropicalaquarium.co.za/showthread.php?9373-Zooms-Article-4-Fertilizers-Substrates-and-CO2

    We've all heard the terms "general hardness" (aka gH), "carbonate hardness" (aka kH) and the more commonly referred to term "pH". I'm going to categorically state right now that if you do not have a fairly accurate way of testing these three within your tank, please do not waste your money on a pressurized CO2!

    "But so-en-so has the same tap water as me, and he is putting CO2 in at 2 bubbles per second..." Is the worst excuse you can come up with. Your TANK is not the same as so-en-so's. And I'm going to try and explain in a bit more detail the concept of marrying these 3 (kh, gh and ph) together.

    Right, let's start with gH. gH (measured in degrees) is a figure representing the general hardness of your water. "General hardness is a measure of the concentration of metal divalent ions such as calcium and magnesium (Ca2+, Mg2+) per volume of water." {http://en.wikipedia.org/wiki/DGH} This hardness is determined by the amount of Calcium and Magnesium that is in your water. The plant experts have determined that in order to get the best plant growth, you need to have a gH of about 4 degrees. Cape Town water is known to have zero hardness, and planted tanks need to have a gH booster added to their tanks. In JHB, if you test your gH, you will find the result rather high, (between 6-8 degrees). BUT this is actually an inaccurate reading because your commercial gH tester is testing for the combined result of Calcium and Magnesium. What your test does NOT tell you is that there is a much higher Calcium concentrate than Magnesium. So based on the quantity of Magnesium, the JHB water is still considered soft, and it is advised to balance out this with an addition of a gH booster to increase the Magnesium. But please do this with caution. I've noticed there is a lot of JHB tanks have explosions of Staghorn algae, which is usually attributed to this Ca to Mg imbalance.

    Let's jump the kH for a paragraph, and look at the pH. "pH (Potential Hydrogen) is a measure of the acidity or basicity of an aqueous solution." {http://en.wikipedia.org/wiki/PH}. Neutral water has a pH of 7.0. If the reading is below 7.0, the solution is considered acidic, and if it goes above 7.0, the solution is considered Alkaline.

    Carbonate Hardness is a measurement of the water's Carbonate content. Within the context of aquaria, the Carbonate hardness acts as a buffer to prevent the pH swing. I'm not going to go into too much detail here, but it is commonly known that pH has a tendency to "swing" within aquariums. It is also commonly known that to have a stable pH is more important than having the "correct" pH within the tank, as the swinging of pH is more detrimental to the health of the fish. The higher the kH, the less the pH will swing, as the kH acts as a buffer to prevent this swinging. Here is a simple diagram to explain:

    [​IMG]


    When CO2 is added to aquarium water, this will naturally alter the pH of the water and make it more acidic. Thus the pH will swing to the acidic side of the scale. At night, when the CO2 is switched off, the pH will slowly swing back. When yoru water's kH is too low, you run the potential risk of experiencing what is commonly termed a pH crash. This is when the pH drops a lot, and very fast. This will kill off your fish overnight. Many members in the Cape have experienced this, and I am aware of a few members in other parts of the country who have also experienced this, even when they thought their kH was high enough.

    Adding Aragonite and Crushed Coral is a common practice with members who are injecting CO2, however this needs to be seen as an insurance against the pH drop, but does not stop that pH swing entirely. I quote a paragraph from an email from Professor @Dirk Bellstedt:
    "When you use CO2 fertilization you need dissolved carbonate to serve as a buffer. Aragonite and crushed coral consist of solid, un-dissolved Magnesium carbonate or Calcium carbonate respectively, and they serve as a buffer in that if the water gets acid (increase in H+ concentration), it literally reacts chemically with the solid carbonate and then this effectively stops the drop in pH because the H+ reacts with the carbonate forming bicarbonate or one step further CO2 and H2O (yes water). However, this is slow acting and does not have the ability to buffer the effect of the acidification of the free CO2 addition, so you need more carbonate hardness from my kH up. The crushed coral you have added is your insurance policy against a pH crash, but to buffer the CO2 you need more carbonate hardness."

    The next question that is often asked when venturing into pressurized CO2 is HOW MUCH CO2 must I add. I'm sorry to say this, but there is no set injection rate here. You may get perfect growth from 1bps, but I may need 5bps. There needs to be extensive (personal) investigation into your tank's behavior (with regards to pH and kH) to determine what rate you are to inject CO2. If you inject too much, you acidify your water and kill your fish. If you inject too little, you land up with algae blooms that are benefiting from the complete imbalance.

    There's one thing that I have learnt over the past few weeks: CO2 is not only finding the balance between nutrients, light and CO2, but also maintaining the balance between Calcium vs. Magnesium (gH), your kH and your pH. If you do not have the knowledge on how to, or the test kits in order to do so, then adding CO2 to your tank may not be the solution for you right now.

    As a side journey, when you are ready to plunge into pressurized CO2, please add the following equipment to your shopping list. A decent quality Bubble Counter, and a Drop checker.

    I didn't bother with either of these for a long time. I was injecting my CO2 through the venturi of an internal pump. So if I wanted to count the bubbles per second, I would simply turn the pump off and count the number of bubbles. What I didn't realize (and thanks to @Sean J for correcting my thinking here) was that the size of a bubble in a proper CO2 Bubble Counter and the size of the bubble from the airline tubing are 2 completely different sizes. I discovered that 2 bubble per second of CO2 through the airline was actually equivalent to approximately 10-15bps through a bubble counter, purely because the bubble in a Bubble Counter is much smaller, and designed for pressurized CO2 injection.

    The second piece of equipment, the drop checker, is simply a visual guide of what is happening to your pH in your tank as you are injecting CO2. It is not a failsafe solution, but it can guarantee that a quick glance of your tank will immediately show you if there is something to be concerned about. As with the Crushed Coral and Aragonite, this should be viewed as an insurance policy for your tank.

    So in summary; firstly, when you are venturing into pressurized CO2, please do not consider it unless you are prepared to put in the extra time and effort into studying your tank and the water chemistry. There is no quick way around putting CO2 into your tank. CO2 is only as safe as the amount of knowledge YOU have. I have been adding CO2 to my tank for over a year now, and my recent research has forced me to now take pH and kH readings every morning and every evening to try and determine what is actually happening, as I have discovered that there is a problem, even though I have not had any major crashes. The readings I am getting have lead me to write this article.

    Secondly, when you purchase your CO2 equipment, make sure you add a decent pH, gH, and kH test kit, along with a good quality bubble counter and Drop checker. I can confirm that these items are actually not as expensive as I originally thought, and @Sean J should be able to help all of you source this equipment.

    And finally, CO2 is not for everyone. Owning a CO2 kit does not put you in an "elite" category of planted tanks. There are many examples of absolutely stunning tanks on this forum where the member is getting stunning results without CO2. CO2 is NOT a magic wand for tanks, and should be treated with the highest respect when being used as an additive to your tank.

    Hope I have given some of you some food for thought!

    Special thanks needs to be given to @Dirk Bellstedt and @Sean J for the knowledge that they have shared with me, and the guidance they have given me over the past few weeks.
     
    Last edited by a moderator: Oct 2, 2016
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  3. wsteene

    wsteene

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    Thanks for the very informative article @Zoom, it definitely answered a lot of my questions regarding introducing CO2. I belief this thread took quite some time to put together and typing it out. Just know it is highly appreciated and adored.
     
    Last edited by a moderator: Oct 2, 2016
  4. OP
    Zoom

    Zoom Retired Moderator

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    It's a pleasure @wsteene. Yes, this article has taken a few days of going back over emails, typing and retyping. However I thoroughly enjoy writing these articles, and if I can help just one person grasp the concept I am trying to get across, then it is all worth it!
     
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  5. wsteene

    wsteene

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    Then I'm that one person you were looking for, it really helped me a lot and cleared the confusion. Spoke to a couple of LFS in town but none could have answered me and some don't know about pressurized CO2. Just love this forum with the advice from the experts. All I need to know in one article. +1 for you @Zoom
     
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  6. Sean J

    Sean J

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    There are a number of things I'd like to add to this, but I don't have the time available right now to do it... I'll type up a lengthy response to this a little later tonight...

    There are very simple ways of clarifying the fundamentals of Co2 injection. And I believe that all planted aquariums will benefit from Co2 injection, not just the high tech aquarium. All plants need carbon to photosynthesize, and personally, I think that the liquid carbon forms are not nearly as effective as pressurized Co2.

    Anyway, I will add to this later on.

    Thanks for the effort @Zoom! It's a good start!
     
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  7. Bazil

    Bazil Bazil

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    Definitely makes sense to someone who wants to go the planted route. Thank you for the info.
     
  8. OP
    Zoom

    Zoom Retired Moderator

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    @Sean J let me clarify my thoughts on that comment... EVERY planted tank WILL benefit from CO2 injection, BUT not every FISHKEEPER has the knowledge to apply CO2. If you know what you are doing and what to look out for, then yes, even a low tech system will benefit from CO2. BUT, if you are just adding CO2 because you want to help the plants, and you haven't researched properly, or tested properly, then you have a time-bomb tank waiting to explode.

    Sean has been through the experience of gassing his fish, and knows all too well the dangers of CO2. Look forward to your addition to this thread!
     
    Last edited by a moderator: Oct 2, 2016
  9. supertramp

    supertramp Supertramp

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    Thanks Zoom, that gets printed and into my fishroom file....some bedside light reading....love it
    Take care
    Rob
     
  10. Drab808

    Drab808

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    very informative!! thanks for this!
     
  11. BBFish

    BBFish Born to Fish Keeping ..... Forced to work

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    Thanks Zoom. You saved my a couple of bucks. I was all geared and ready to convert a spare 2Kg Co2 Fire extinguisher, now i'll rather support a local product called "Scape liquid Carbon" to provide carbon for my semi planted tank.
     
  12. f-fish

    f-fish #unspecified

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    Just an FYI ... you can check on a profile of somebody if they are still around. In this case

    Zoom was last seen: Nov 23, 2016


    Sean is still around - wonder if he ever finished that thought
    or that was one heck of a night or a very long response.

    But the good thing the information in these old threads still have value even if the OP is MIA.


    Later Ferdie
     
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  13. BBFish

    BBFish Born to Fish Keeping ..... Forced to work

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    Thanks f-fish, newbie around here
     
  14. f-fish

    f-fish #unspecified

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    All good, but it is nice to see the old threads getting well deserved attention.
     
  15. EugeneAqua

    EugeneAqua

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    Great post, considering C02 and this plugged a big gap in my knowledge base as it covered an area that many articles have not, especially with regard to local water knowledge. Still of great value in 2018.
     

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