Post by andrew on Mar 1, 2020 16:34:07 GMT -5
I would like to discuss the differences in concentrations of CO2 in natural bodies of water and home aquariums, in order to better understand if we as aquarists can increase CO2 levels in our tanks above atmospheric levels without injecting CO2. I will talk a little about what I have found and if you would like to read for yourself I found a lot of info googling "carbon dioxide in natural waters" and "carbon dioxide in wetlands"
I have been interested in soil substrate planted tanks for awhile and am always trying to learn more. Let me be clear that even though many dirt bottom tanks use just separated or mineralized topsoil this is not really soil in the true its true sense. Soil is a mixture of varying quality organic matter (it will have organic matter categorized by it's availability and/or time frame for decomposition) and sediments in varying proportions, chemical make up, and size. I had one tank (150 gallons) for about three years with swordtails and plants, that did very well. Although there are definite drawbacks to using soil. I believe these drawbacks are offset by the many benefits of soil on plant health/growth but also overall health of the aquarium inhabitants. Soil substrates in natural waters have varying levels organic matter and mineral nutrients in the soil. Often places where plants and fish are found there are at least moderate levels of these two major components soil. In earth bottomed shrimp aquaculture ponds this is often also the case. Although this is a stretch for some as it also means possibly more nitrogen compounds available to the water column once broken down to ammonium and potentially higher levels of pathogenic bacteria in the aquarium, some will argue this. To each their own I guess. I don't feel that raising fish in sterile tanks makes them healthier than other fish. Conversely, I do not want to put fish muddy algae blooming water filled with parasites, viruses, or harmful bacteria. I think keeping species specific tanks where one can target parameters ideal for that animal creates really healthy fish. I read somewhere that fish do not live in sterile water in the wild but in biologically clean water. I like livebearers and my local water is a little alkaline and moderately hard so it works out great. I read an article in the 2hr aquarist that talked about soil bottom tanks for fragile inverts. It said that they are very likely to eat and forage on the bacteria and biofilm produced by organic matter and certain bacteria strains working together. I like to add shrimp, snails, and copepods to my tanks before I add any fish.
I have poked around on the net and found several different sources examining the carbon cycle. I am trying to understand how I could achieve aquarium CO2 levels higher that atmospheric levels, without injecting CO2. I found many different resources that talked about carbon sources and sinks within natural bodies of water. I learned that larger, deeper, and cooler bodies of water contain less CO2 that smaller, shallower, and warmer waters. However, both are almost always above atmospheric CO2 levels sometimes much higher. I don't know what this would equate to in ppm because the literature did not use ppm and a measurement. I just know that these waters were much higher in CO2 that what what provided by the atmosphere.
One definite source of CO2 in natural waters is organic carbon sources being decomposed by soil microbes and converted to CO2.
A second possible source of CO2 is an acid base reaction that produces CO2. Magnesium carbonate (dolomite) or calcium carbonate (limestone, 10% of all sedimentary rocks, very common) and any aqueous acid will react to produce CO2. The equation for magnesium carbonate is: MgCO3 + 2 HCL = MgCl2 + CO2 + H2O (this equation moves from left to right and does not go either way). I read somewhere that Magnesium Carbonate produces much more CO2 that Calcium Carbonate in this type of reaction. I have not been able to find anything that corroborated what I read on that particular page. I think because calcium and magnesium are important to plant and fish life this reaction could prove useful in the an aquarium with fish that would like the pH slightly alkaline in the 7.5-8.0 range like livebearers and a rise in GH from what your tap water is. Hopefully, there is someone here that has a chemistry background who can clarify the difference between these reactions and the energy produced.
Another source that is believed to be significant is groundwater. This is likely due to the combination of organic matter decomposition and similar acid base reactions happening under ground in the water. Calcium carbonate is often found in underground aquifers where CO2 and other acids in the water carve out caves and stalactites.
Interestingly, levels of dissolved CO2 are higher in the wet season. More water is absorbed into the ground where it flows through earth that contains carbon containing organic matter being decomposed. Also, plant matter in the run off water gathers in streams then lakes increasing organic matter sedimentation and decomposition. Additionally, warmer regions are greater sources of CO2 than cooler regions because of several factors. These include increased growth rates of plants leading to more organic matter being decomposed and greater bacterial decomposition rates and higher temperatures.
Finally, things I've found or read that impact the CO2 concentrations in natural bodies of water: water temperature, water depth, total water volume, wet/dry seasons, Carbon:Nitrogen ratio of organic matter in sediment (quality of organic matter), bacterial species performing the decomposition (some produce more energy in the form of CO2 than others), fish respiration, and CO2 uptake by plants.
I have some ideas to create an environment with CO2 levels adequately above the atmosphere/water equilibrium commonly thought to be the maximum level possible without injecting CO2 into your tank. This is simply not true depending on your setup and there is much information to back this up.
1) I could use a soil substrate (compost with no manure added because of pathogenic bacteria present in it) with levels of carbon to nitrogen around 30:1 - 40:1, C:N. This will slow down decomposition and limit nitrogen mineralization into the aquarium environment. Use compost that is very fine texture as this is material that will be broken down faster, within the next 1-5 years.
2) I could try bacterial inoculation with use of worm castings, compost, and commercial inoculants. Looking for inoculants that nitrify, denitrify, and breakdown organic matter are necessary.
3) I should keep parameters ideal for bacterial populations. Fine air stone use for O2 and power heads moving O2 around the tank and into sediment, heater, pH 7.5-8.0. (pH could be as low as 6.0 if your fish require this.)
4) I need to build a soil that will resist becoming overly anaerobic at the bottom layers by using a variable sized volcanic sand very fine to fine, 1/32" to 1/8" approximately, mixed in to soil to add macro and micro pore space so O2 rich water can move through it keeping conditions out of very anaerobic states. As soil becomes more anaerobic it produces less CO2 from microbial decomposition.
5) I can use calcium carbonate and magnesium carbonate reactions to add CO2 by either adding granular calcium carbonate or magnesium carbonate to the soil, canister filter, or both to react with acids produced by organic matter decomposition and humic acids in the soil. I would use a varied size granular if mixed with soil because it will react more linearly and gradually overtime than powders.
6) I will use a mixture of potting soil, compost, and humus that has been mechanically separated by water to remove all floating matter. I'll also let the soils sit in the water after being separated to leach out excess tannins I don't like tea colored water and don't want my water softened by the tannins. Then I'll mix equal parts of each as my organic matter portion of my soil, topped off with a cup or two of worm castings and use as this mix as my organic matter soil component. Potting soil should provide organic matter that will be very fine and will decompose shortly providing a boost to bacteria when starting a new tank, compost should give me a more ideal C:N ratio for CO2 production while providing matter that will decompose more slowly, and humus should among other soil fertility enhancements add an additional source of acids to react with the MgCO3 and CaCO3 while not much decomposition will take place with humus component of soil.
7) I have considered adding peat moss to the organic matter or canister filter to further lower the pH. But I do not want the tea colored water that you get with using peat. I don't think the soil pH being a few tenths lower will greatly increase the CO2 production. Plus peat will not decompose in my tank within the time period people normally keep aquariums and therefore add not much benefit with these other organic matter sources being used. Peat moss is what is left when decomposition of aquatic plants is almost complete in peat bogs. That could be a good or a bad thing depending on how long I want my tank to last. Peat is also a great fertility booster when fertilized properly. It has a very high cation exchange capacity as dose most organic matter.
8) I have thought about using vinegar to lower pH and provide acid to react with the MgCO3 and CaCO3. How I would do this is unclear to me and I would have to do some experimenting to see how much vinegar to add to lower the pH within and acceptable range maybe +/- .05. I have also thought about mixing vinegar and MgCO3 powder (in a sealed water bottle so that I do not off gas all of the CO2) to a pH around 8.0 then adding it to my aquarium water. This would defeat the purpose of what I am trying to do and would likely result in more work that I want to do daily to maintain my aquariums.
9) I think having very strong bacterial populations and dosing benificial bacteria should allow me to push my stocking levels and produce more CO2 constantly. Provided I can find one that actually works the way it is described. I have only ever used the bacteria balls that come from Great wave engineering that I got with some media I purchased from them. They are supposed to add nitrifying and denitrifying bacteria but I never tested ammonia, nitrate, or nitrites to see if this was the case with my last aquarium. I was just lucky I never had any issues with fish health other than a crappy heater that fried some of my fish when I first got started.
10) I though about possibly using a UV sterilizer to also allow for a higher population densities in the aquarium. It will reduce oxidative stress and give me more healthy fish and inverts that will eat more, move more, and breathe more resulting in more CO2 coming from respiration.
11) I could use a lights out period in the middle of the photoperiod about 2-3 hours long to boost CO2 levels in water.
I would like to test what produces more CO2, CaCO3 or MgCO3 when reaction with an aqueous acid is complete. Furthermore, I would like to know which produced more CO2 the quickest as this is also important in deciding which to use or what proportions to use of each. From what I have read CaCO3 reacts faster and produces less CO2 that MgCO3. So a mixture of 4:1, calcium:magnesium, (CaCO3)/Limestone:(MgCO3)/Dolomite should provide a biologically appropriate ratio and would likely be my best bet over time for the health of my fish, inverts, and plants. I could use my acidic organic soil mix and add CaCO3 and MgCO3, one part soil to ten parts water in a glass bottle (roughly the proportion of soil to water in my aquarium) and add set mount of either carbonate (enough not to limit/stop the reaction because of inadequate carbonates during that month) to each glass bottle and place a small ballon over each bottle to see how much if any gas is produced and monitor this over a month to confirm that CO2 is produced over different time periods depending on grain size and carbonate compound used. I could either let the experiment run the full month letting CO2 build up or if being produced fast enough daily or weekly remove ballon and weigh it to see how its production changes over the month. I could then possibly extrapolate how long the carbonates will last in the aquarium soil if I see certain things changing.
I would also like to test different bacterial inoculants for CO2 production resulting from microbial decomposition of soil without any fish food or added fish/invert waste. Those amounts will change slightly day to day anyway and fish food and waste don't contain carbon. All it would do is provide more ammonium or nitrogen to be consumed by bacteria if there wasn't a sufficient carbon to nitrogen ratio in the organic matter being decomposed. I can test this by using my prepared soil, one part soil to ten parts water then adding a small amount of inoculant and then shaking it or stirring it several times a day for a month. I could watch what happens to the ballon over that month weighing CO2 in the balloons every week or daily if being produced fast enough although I want to limit the amount of times I take the ballon off and on so that I don't lose CO2 when the pressure changes in the bottle from removing the ballon.
If anyone has any input I would appreciate it. If anyone is interested in this topic lets talk about it here where others can learn from it. If anyone questions the information I have given say so and I will try to find my source of the information.
I have been interested in soil substrate planted tanks for awhile and am always trying to learn more. Let me be clear that even though many dirt bottom tanks use just separated or mineralized topsoil this is not really soil in the true its true sense. Soil is a mixture of varying quality organic matter (it will have organic matter categorized by it's availability and/or time frame for decomposition) and sediments in varying proportions, chemical make up, and size. I had one tank (150 gallons) for about three years with swordtails and plants, that did very well. Although there are definite drawbacks to using soil. I believe these drawbacks are offset by the many benefits of soil on plant health/growth but also overall health of the aquarium inhabitants. Soil substrates in natural waters have varying levels organic matter and mineral nutrients in the soil. Often places where plants and fish are found there are at least moderate levels of these two major components soil. In earth bottomed shrimp aquaculture ponds this is often also the case. Although this is a stretch for some as it also means possibly more nitrogen compounds available to the water column once broken down to ammonium and potentially higher levels of pathogenic bacteria in the aquarium, some will argue this. To each their own I guess. I don't feel that raising fish in sterile tanks makes them healthier than other fish. Conversely, I do not want to put fish muddy algae blooming water filled with parasites, viruses, or harmful bacteria. I think keeping species specific tanks where one can target parameters ideal for that animal creates really healthy fish. I read somewhere that fish do not live in sterile water in the wild but in biologically clean water. I like livebearers and my local water is a little alkaline and moderately hard so it works out great. I read an article in the 2hr aquarist that talked about soil bottom tanks for fragile inverts. It said that they are very likely to eat and forage on the bacteria and biofilm produced by organic matter and certain bacteria strains working together. I like to add shrimp, snails, and copepods to my tanks before I add any fish.
I have poked around on the net and found several different sources examining the carbon cycle. I am trying to understand how I could achieve aquarium CO2 levels higher that atmospheric levels, without injecting CO2. I found many different resources that talked about carbon sources and sinks within natural bodies of water. I learned that larger, deeper, and cooler bodies of water contain less CO2 that smaller, shallower, and warmer waters. However, both are almost always above atmospheric CO2 levels sometimes much higher. I don't know what this would equate to in ppm because the literature did not use ppm and a measurement. I just know that these waters were much higher in CO2 that what what provided by the atmosphere.
One definite source of CO2 in natural waters is organic carbon sources being decomposed by soil microbes and converted to CO2.
A second possible source of CO2 is an acid base reaction that produces CO2. Magnesium carbonate (dolomite) or calcium carbonate (limestone, 10% of all sedimentary rocks, very common) and any aqueous acid will react to produce CO2. The equation for magnesium carbonate is: MgCO3 + 2 HCL = MgCl2 + CO2 + H2O (this equation moves from left to right and does not go either way). I read somewhere that Magnesium Carbonate produces much more CO2 that Calcium Carbonate in this type of reaction. I have not been able to find anything that corroborated what I read on that particular page. I think because calcium and magnesium are important to plant and fish life this reaction could prove useful in the an aquarium with fish that would like the pH slightly alkaline in the 7.5-8.0 range like livebearers and a rise in GH from what your tap water is. Hopefully, there is someone here that has a chemistry background who can clarify the difference between these reactions and the energy produced.
Another source that is believed to be significant is groundwater. This is likely due to the combination of organic matter decomposition and similar acid base reactions happening under ground in the water. Calcium carbonate is often found in underground aquifers where CO2 and other acids in the water carve out caves and stalactites.
Interestingly, levels of dissolved CO2 are higher in the wet season. More water is absorbed into the ground where it flows through earth that contains carbon containing organic matter being decomposed. Also, plant matter in the run off water gathers in streams then lakes increasing organic matter sedimentation and decomposition. Additionally, warmer regions are greater sources of CO2 than cooler regions because of several factors. These include increased growth rates of plants leading to more organic matter being decomposed and greater bacterial decomposition rates and higher temperatures.
Finally, things I've found or read that impact the CO2 concentrations in natural bodies of water: water temperature, water depth, total water volume, wet/dry seasons, Carbon:Nitrogen ratio of organic matter in sediment (quality of organic matter), bacterial species performing the decomposition (some produce more energy in the form of CO2 than others), fish respiration, and CO2 uptake by plants.
I have some ideas to create an environment with CO2 levels adequately above the atmosphere/water equilibrium commonly thought to be the maximum level possible without injecting CO2 into your tank. This is simply not true depending on your setup and there is much information to back this up.
1) I could use a soil substrate (compost with no manure added because of pathogenic bacteria present in it) with levels of carbon to nitrogen around 30:1 - 40:1, C:N. This will slow down decomposition and limit nitrogen mineralization into the aquarium environment. Use compost that is very fine texture as this is material that will be broken down faster, within the next 1-5 years.
2) I could try bacterial inoculation with use of worm castings, compost, and commercial inoculants. Looking for inoculants that nitrify, denitrify, and breakdown organic matter are necessary.
3) I should keep parameters ideal for bacterial populations. Fine air stone use for O2 and power heads moving O2 around the tank and into sediment, heater, pH 7.5-8.0. (pH could be as low as 6.0 if your fish require this.)
4) I need to build a soil that will resist becoming overly anaerobic at the bottom layers by using a variable sized volcanic sand very fine to fine, 1/32" to 1/8" approximately, mixed in to soil to add macro and micro pore space so O2 rich water can move through it keeping conditions out of very anaerobic states. As soil becomes more anaerobic it produces less CO2 from microbial decomposition.
5) I can use calcium carbonate and magnesium carbonate reactions to add CO2 by either adding granular calcium carbonate or magnesium carbonate to the soil, canister filter, or both to react with acids produced by organic matter decomposition and humic acids in the soil. I would use a varied size granular if mixed with soil because it will react more linearly and gradually overtime than powders.
6) I will use a mixture of potting soil, compost, and humus that has been mechanically separated by water to remove all floating matter. I'll also let the soils sit in the water after being separated to leach out excess tannins I don't like tea colored water and don't want my water softened by the tannins. Then I'll mix equal parts of each as my organic matter portion of my soil, topped off with a cup or two of worm castings and use as this mix as my organic matter soil component. Potting soil should provide organic matter that will be very fine and will decompose shortly providing a boost to bacteria when starting a new tank, compost should give me a more ideal C:N ratio for CO2 production while providing matter that will decompose more slowly, and humus should among other soil fertility enhancements add an additional source of acids to react with the MgCO3 and CaCO3 while not much decomposition will take place with humus component of soil.
7) I have considered adding peat moss to the organic matter or canister filter to further lower the pH. But I do not want the tea colored water that you get with using peat. I don't think the soil pH being a few tenths lower will greatly increase the CO2 production. Plus peat will not decompose in my tank within the time period people normally keep aquariums and therefore add not much benefit with these other organic matter sources being used. Peat moss is what is left when decomposition of aquatic plants is almost complete in peat bogs. That could be a good or a bad thing depending on how long I want my tank to last. Peat is also a great fertility booster when fertilized properly. It has a very high cation exchange capacity as dose most organic matter.
8) I have thought about using vinegar to lower pH and provide acid to react with the MgCO3 and CaCO3. How I would do this is unclear to me and I would have to do some experimenting to see how much vinegar to add to lower the pH within and acceptable range maybe +/- .05. I have also thought about mixing vinegar and MgCO3 powder (in a sealed water bottle so that I do not off gas all of the CO2) to a pH around 8.0 then adding it to my aquarium water. This would defeat the purpose of what I am trying to do and would likely result in more work that I want to do daily to maintain my aquariums.
9) I think having very strong bacterial populations and dosing benificial bacteria should allow me to push my stocking levels and produce more CO2 constantly. Provided I can find one that actually works the way it is described. I have only ever used the bacteria balls that come from Great wave engineering that I got with some media I purchased from them. They are supposed to add nitrifying and denitrifying bacteria but I never tested ammonia, nitrate, or nitrites to see if this was the case with my last aquarium. I was just lucky I never had any issues with fish health other than a crappy heater that fried some of my fish when I first got started.
10) I though about possibly using a UV sterilizer to also allow for a higher population densities in the aquarium. It will reduce oxidative stress and give me more healthy fish and inverts that will eat more, move more, and breathe more resulting in more CO2 coming from respiration.
11) I could use a lights out period in the middle of the photoperiod about 2-3 hours long to boost CO2 levels in water.
I would like to test what produces more CO2, CaCO3 or MgCO3 when reaction with an aqueous acid is complete. Furthermore, I would like to know which produced more CO2 the quickest as this is also important in deciding which to use or what proportions to use of each. From what I have read CaCO3 reacts faster and produces less CO2 that MgCO3. So a mixture of 4:1, calcium:magnesium, (CaCO3)/Limestone:(MgCO3)/Dolomite should provide a biologically appropriate ratio and would likely be my best bet over time for the health of my fish, inverts, and plants. I could use my acidic organic soil mix and add CaCO3 and MgCO3, one part soil to ten parts water in a glass bottle (roughly the proportion of soil to water in my aquarium) and add set mount of either carbonate (enough not to limit/stop the reaction because of inadequate carbonates during that month) to each glass bottle and place a small ballon over each bottle to see how much if any gas is produced and monitor this over a month to confirm that CO2 is produced over different time periods depending on grain size and carbonate compound used. I could either let the experiment run the full month letting CO2 build up or if being produced fast enough daily or weekly remove ballon and weigh it to see how its production changes over the month. I could then possibly extrapolate how long the carbonates will last in the aquarium soil if I see certain things changing.
I would also like to test different bacterial inoculants for CO2 production resulting from microbial decomposition of soil without any fish food or added fish/invert waste. Those amounts will change slightly day to day anyway and fish food and waste don't contain carbon. All it would do is provide more ammonium or nitrogen to be consumed by bacteria if there wasn't a sufficient carbon to nitrogen ratio in the organic matter being decomposed. I can test this by using my prepared soil, one part soil to ten parts water then adding a small amount of inoculant and then shaking it or stirring it several times a day for a month. I could watch what happens to the ballon over that month weighing CO2 in the balloons every week or daily if being produced fast enough although I want to limit the amount of times I take the ballon off and on so that I don't lose CO2 when the pressure changes in the bottle from removing the ballon.
If anyone has any input I would appreciate it. If anyone is interested in this topic lets talk about it here where others can learn from it. If anyone questions the information I have given say so and I will try to find my source of the information.
