The Unknown Parameter

Discussion in 'Water Chemistry' started by Wrassman, Jun 3, 2003.

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  1. Wrassman

    Wrassman Peppermint Shrimp

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    [glow=Blue, 2, 99%]The Unknown Parameter

    We spend a lot of money, time, and energy on certain supplements we put in our aquariums:  Calcium, Alkalinity, Salinity, Magnesium, Iodine, Trace Elements, pH, and the list could go on and on.  There is one overlooked element in our systems that is SO important, we couldn't have a system without it.  Yet, you can look back over months and months of articles in Aquarium Magazines, and not find one article dedicated to it.

    I suppose part of the reason is that it is really not a supplement.  In fact, if you have to add this element to the aquarium as an additive, you've most certainly got problems!!  And if I asked you to test for it, you wouldn't know what the proper parameters are anyway.

    I'm talking about Oxygen.

    Our modern tanks are so enclosed, in an effort to prevent evaporation, salt creep, and fish jumping to their deaths.  However, in an attempt to fix these problems, we have created other problems in our tanks: low oxygen levels, high levels of carbon dioxide, and just stangnant air.  Many people are starting to think about ways to provide opportunites for fresh air, mainly oxygen, to be brought into our systems.

    One good way of providing oxygen in a tank is through bubble-stones (wooden ones are best), and allowing those bubbles to move water (agitate) across the tank.  This was one of the "plusses" of UG filters; the air-stones provided great oxygen levels in the tank.  Further, they moved water with little oxygen to the top of the tank where it could be exposed to more oxygen.  But, no one uses UGFs any more.

    A better way would be to use a powerhead with an aeration feature, to simply to move water across the surface of the tank.  This water agitation, along with the bubbles in the aeration, is an excellent way of causing gas exchange.  Not only is oxygen brought into the water during this process, but carbon dioxide and other, more noxious gases are allowed to be released.[/glow]

    [glow=Green, 2, 99%]Let's talk about Carbon Dioxide, for a moment.

    You do NOT want a build up of CO[sub]2[/sub] in your system.  Those of you with Calcium Reactors need to be very cautious of this.  A build-up of CO[sub]2[/sub] in your system will cause a drop in pH.  If the pH drops below 7.8 in a marine system, denitrifying bacteria will stop functioning.  The result is a build up of ammonia and nitrite.

    But, before all that has happened, your fish have been lying on the bottom of the tank, breathing heavily.  If you allow the CO[sub]2[/sub] to get too high, the fish will simply go to sleep, and not wake up.[/glow]

    [glow=Blue, 2, 99%]So, you don't want CO[sub]2[/sub] in your tank in high concentrations.  You want to keep some macroalgae growing in  your tank or sump somewhere to utilize the CO[sub]2[/sub], and give off some oxygen.  Plants are a very good way of providing oxygen to a tank.  But, unless your marine tank is very small or you have LARGE amounts of macroalge growing in it, the amount of oxygen provided by the plants will not be sufficient.

    Today, the best way of providing oxygen to a marine tank is with a protein skimmer, particularly a venturi type.  A venturi type protein skimmer is filled with millions of micro bubbles of oxygen, which are used to foam to the top of the skimmer and collect waste.  The rest of the water is then dumped back into the tank or sump, having been "oxengenated" by all the bubbles in the skimmer.

    Some people even feed their skimmers with ozone (O[sub]3[/sub]), in order to kill unwanted parasites and the like, but also to raise the oxygen level in the tank, and the redox potential of the water.

    As I stated in my Review of the Sochting Oxydator A, I opted out of the ozonizer route, and went instead with the Oxydator, which puts 270mg of Oxygen (O[sub]2[/sub]) into the water every day.  I have the unit in the sump with my skimmmer, so that most of the oxygenated water is picked up by the skimmer. I know this because my sump is only 20g, and my AquaMedic Turbofloater runs around 600gph.
    ------------------------------------------------------------------------

    If you are interested in the O[sub]2[/sub] levels in your tank, you should have 6-7ppm of oxygen in your water.  The saturation point is 11ppm, and you are going to be "oxidizing" fish and everything else at that level.  I would like to think that, with my equipment, etc., I am running at 7ppm or above right now.  I guess I should get a test, huh?

    I'll be glad to answer any questions you have about the current article.  Please, fire away!!!

    Next, Oxygen and the Nitrogen Cycle... [/glow]

    Thanks to Frakes and Moore for providing some information that started this project.
    http://thatwebplace.hypermart.net/aquatic/seascope/aeration.html

    EDIT: Spelling, grammar, and clarity... [smiley=square.gif]
     
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  3. Matt Rogers

    Matt Rogers Kingfish Staff Member

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    I am so glad you brought up Oxygen. [smiley=thumbs_up.gif] [smiley=thumbs_up1.gif]


    It amazes me that it hardly ever comes up anymore. It's the first thing I think about when I hear people say they are going to get rid of their skimmer.
     
  4. Wrassman

    Wrassman Peppermint Shrimp

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    [glow=Green, 2, 80%]I agree. It's one of the issues concerning the Ecosystem that I never have understood. I've seen the algae sumps for these systems, and it just does NOT seem like enough macroalgae to keep the O[sub]2[/sub] level up to where it needs to be. And if you are like me and like a large bio-load, your tank is going to run high on CO[sub]2[/sub], low on pH, and low on O[sub]2[/sub].

    If someone who has an Ecosystem and knows how the Oxygen is handled in that system would chime in and explain it to me, I would greatly appreciate it.[/glow]
     
  5. Wrassman

    Wrassman Peppermint Shrimp

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    [glow=Brown, 2, 90%]I have gone to the main site of EcoSystem Aquarium, and even though much information is provided, I could not find any articles or studies as to the O[sub]2[/sub] in their systems. As I said, much information was provided in the study of two tanks over a 3 month period, monitoring everything from pH to DOCs. Unfortunately, there wasn't an oxygen column in the tables.

    Again, if you know how EcoSystems produces viable levels of oxygen in their systems without protein skimmers, and without any sort of "aeration," please pass that information along. I am not "attacking" EcoSystems at all -- I am simply trying to understand how they work, and pass that information along to others here.

    For those interested, here is the link to EcoSystems Aquarium:[/glow]

    http://www.ecosystemaquarium.com/index.html
     
  6. CheckMateKingll

    CheckMateKingll Feather Duster

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    Wrass,,,
    Now that you mention it,,,
    I have noticed that since I have installed my Eco-System that I have been unable to get my PH over 8.1, maybe 8.2 lower end.
    I do know that when I open my windows the PH rises for a few days to 8.2 to 8.3,,,
    Down here in South Florida there is only a few months that we keep our windows open, most of the time the A/C is going.
    I just read your post on the Oxydators and I think it would be something to try in my situation, what the heck, I have tried everything else including air stones in the sump,,,
    Wrass can you tell me how tall and wide the Oxydator is???
    Tanks

    Edit by Wrassman:
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  7. Apophis924

    Apophis924 Astrea Snail

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    Has anyone looked into the effect Macro algea has on O2 in the reef tank. I know that my Refugium is full of sevreal types of algea and it is lit 24/7. I do not know how mych O2 they add to the system but i do know they remove a LOT of CO2. since the algea has been growing wild my Ph leves do not have such a drastic drop when the main tank lights are off. and now when i close the windows the ph will remain fairly stable. Before i had the fuge and was using cirulation and powerheads for agitiation. I still had wide ph swings due to CO2 build up at night and when the windows were shut. Granted it takes a LOT of algea to make a difference but it is more nautral and stable then constantly adjusting skimmers and cleaning air stones. MY tank is a 20 gallon nano. I dont know if this applies to larger systems, But it should since it works in the ocean the largest reef tank i know of.
     
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  9. tankgirl

    tankgirl Plankton

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    I have to turn down my overflow, if I don't I get microbubbles in the tank. Just wanted to mention that as an additional way of oxygenating the water.
    Also, can anyone tell me the levels of CO2 in NSW? Or what a normal level is?
     
  10. Craig Manoukian

    Craig Manoukian Giant Squid

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    TG,

    Here are  a couple of links to a general discussion of the oceans ability to store CO2.  the information suggests that the amount of CO2 absorption in the ocean is temperature sensitive.  I seems like the natural range of CO2 is very dependant on temperature and may variy from ocean to ocean as you move away from the equator, eh?

    Very interesting topic as it is a global issue related to global warming!


    http://coexploration.org/bbsr/classroombats/html/co2_in_the_sea.html

    http://climatechange.unep.net/jcm/doc/jcm/pan/carbonplot.html
     
  11. Guest

    Guest Guest

    I have set up my reef tank after several years of being dismantled. I have a 120 gallan tank, with a trickle filter, Berlin skimmer, and external Little Giant 1,200 gph pump. I have seen many tanks that have crystal clear water with no bubbles present. My tank continously pumps small bubbles back into the tank through the external pump. I have disconnected my protein skimmer to see if that fixes the problem with no luck. I know that oxygen is necessary but I would like to provide a clearer viewing area with no bubbles. Is there anything that I can do to reduce the bubble content from the time the water leaves the trickle filter to reentering the tank?
     
  12. Matt Rogers

    Matt Rogers Kingfish Staff Member

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    Just a stab in the dark, but the little giant is connected to a bulkhead on the sump, put a 90 degree elbow on the other side of the bulkhead. Have the end of the bulkhead pointing towards the bottom of the sump. This will force the water to be drawn from the bottom rather than close to the surface.

    Otherwise, use a sponge divider in the sump. Or both.


    :)