Do you guys test for oxygen? I've never tested my small pond so I figured the kit i ordered would test for that, but now I just looked at the description online and it only tests for nitrate, nitrite, PH, hardness, and ammonia. I was waiting to put my koi in the new pond until I found out if my O2 level was good,now I find out I cannot even do that with this test. I don't see too many tests that do dissolved oxygen, is this something you can just ignore? Seems weird because koi need a lot of oxygen. Anyway, I think I'm going to start the move tonight because my new pond certainly doesn't have any ammonia or any other bad thing in it right now with no fish. Let me know about the O2, pretty curious about that.
Oxygen Content
- Thread starter buckry
- Start date
crsublette
coyotes call me Charles
Simple answer is ... testing for dissolve O2 is not important as long as you have mechanisims such as an aerator stone or waterfalls or fountain to stir up the water. It is the atmospheric pressure on water that oxidates waters. The aforementioned mechanisms pull the water from the bottom of the pond, which is less O2 saturated and higher CO2 saturated, to the top of the pond so the atmospheric pressure can oxygenate it and more CO2 can be released. Generally, not healthy when ya see fish going to the surface to gulp for air; this might be an indicator of low O2.
If you want to still test for dissolved O2, then check out the Milwaukee manufacturer. Their O2 test is under $200 (usa) and I just recalibrate it once a month, sometimes more if I want to take the time.
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Be careful how many fish, especially koi, when dealing with a brand spank'n new water or after a very thorough pond cleaning. The water has to grow some algae or bacteria colonies for the nitrification process to remove the toxic Ammonia and Nitrites. Koi are well known to be heavy Ammonia producers. If ya want to learn more, then check out when to start adding fish.
-------------------------
I like the liquid test kits. I do not like the paper test strips since all they give is a "general idea" of something in the water. The electronic testers are expensive and require calibrations, sometimes often.
Love to ramble. So, in my rambling effort, hope it shines some light.
-------------------------
Good ya are being proactive about testing. My understanding is that most folk don't do it until there is a problem; honestly, by then, might be too late if ya don't like seeing death, when it happens, floating around in the water. From what I understand, extensive testing is mostly done by breeders, sellers, and avid hobbyists.
I enjoy being an avid hobbyist. I test for mostly everything, which is temperature, NH3 (ammonium, which is ionized ammonia), NH4 (unionized ammonia), nitrite, KH, GH, pH, nitrate, phosphorus, dissolved O2, salinity, total dissolved solids (TDS), and oxidation reduction potential (ORP). I only do the these tests once a week or bi-weekly, which take me between 30~45 minutes. There are more parameters such as copper, iodine, and others, but these "other" parmeters are mainly of concern to other areas such as maintaining reefs and aquatic breeders.
Primary tests, most Important. Temperature, ammonia (NH4 & NH3), nitrite (NO2), KH, and ((GH and pH if you have soft water )). To keep this brief, going to let my references, at end of my post, talk about the chemistry.
- Temperature : tells ya when to feed fish certain types of food and when to stop/start feeding fish. certain fish ailments can be fixed by water temperature.
- Ammonia (NH3) : safe form of ammonia to fish except temperature and pH will determine how much of NH3 will become the toxic, NH4, ammonia. Most Ammonia tests will combine NH3 and NH4 in the reading.
- Ammonia (NH4) and Nitrite : these two are very toxic to fish. these two will lower a fish's immune system making them more susceptible to ailments and death. Seachem provides a good liquid test kit to test specifically for NH4. Algae is also a plant that consumes ammonia directly, bypassing nitrification, so you may see an influx of algae of all types (string, floating, single cell) appear in the water.
- KH : buffers the lower spectrum of pH. if you have an acidic pH problem (that is below 7), most often it is due to low KH, called carbonate hardness. Soft water tends to have very low KH. If you are trying to use a pH down product or other acids, then the volume of KH will determine how much product will be required to lower the pH. The acids must first dissolve the KH; then, the pH will lower. Rain water is an example of water with very low KH; de-ionized reverse osmosis water has zero KH. KH is lowered with acids to dissolve the KH or by diluting the water with a more acidic, or softer water, such as rain or di-RO water. Also, nitrification will produce nitric acids that will slowly consume KH dependent upon the volume of Ammonia that needs to be consumed throughout the process. Nitrification is the process of bacterias and other organisms converting Ammonia to Nitrite then Nitrite to Nitrate then finally Nitrate to Nitrogen gas.
- GH : buffers the higher spectrum of pH. the higher pH will increase convert more NH3 to NH4. If you are adding Baking Soda to raise your KH, then your water could become very alkaline (pH 8 or above) if your GH is very low. Rain water tends to have lower GH; regular 2 stage reverse osmosis water (with a .1 micron filter) will have a very low GH. Various products can increase GH; beware, some products may increase salinity and, if ya ever have to treat your pond, then the salinity level will determine the effectiveness of medications. Fish need a healthy level of GH to help with osmosis regulation.
- pH : general indicator telling you if your water is acidic (below 7), neutral (7), and alkalinity (above 7). pH is determined by the volume and mutual exclusive relationship between KH and GH. "Total hardness" is a very vague test that tells ya how much KH and GH is available in the water. If your "total hardness" is low, then your pH will likely be more acidic.
Secondary tests. Nitrate (NO3), Phosphorus, dissolved O2, salinity.
- Nitrate (NO3) : Natural plant and algae fertilizer. At extremely high levels, nitrate will obstruct fish's osmosis regluation and retard the nitrification process causing a high volume of Nitrites.
- Phosphorus : One component consumed by algae when actively growing.
- dissolved O2 : nitrification and fish require a particular volume of dissolved O2 to survive. Temperature, heavy ammonia processing, algacides, and other medications can significantly change dissolved O2 volume.
- salinity : influences fish's osmosis regulation. It can force fish to build an extra coat of slime to fend of parasites, but also can lower the effectiveness of medications.
Other tests. total dissolved solids (TDS), and oxidation reduction potential (ORP).
- TDS : measures any particulates floating in the water. If you want to know how clear your water is, then do a TDS test. These tests can also be calibrated to be a salinity test.
- ORP : basically, measures the waters electrical charge in the water. this charge will determine how well particular oxidizers will work in the water. Salts change this chrage so ORPs can be calibrated to be a salinity tester. ORPs most often used when treating the water with medications that require a level of oxidization to be successful.
----------------------
I think this will give ya a basic start. Forum members here may likely have better references. Some of this stuff I use more as a guideline rather than a rule to follow.
What is the best way to lower KH and GH ?
Of course, we must talk about hardness
KH, pH, and don't assume everyth's ducky
Is it possible for Muratic acid to do some real damage while lowering pH?
Ammonia toxicity relationship to water temperature
(( grr, also have an article talking about how pH changes ammonia toxicity; sorting through my 50 or so unorganized bookmarks ))
Do fish drink? Fish osmoregulation and RO water
Soft water or hard water, which is best?
Adjusting KH and GH (( i just use this a general benchmark, I don't adhere to it 100% ))
When to start adding fish
Dissolve Oxygen water saturation levels for fish.
If all someone says is "it worked for me", then raise a skeptical eyebrow; often, something will "work" until it does not "work" so then it is changed so it will "work". Often, I have found out about this hobby, just like anything else, is that testimonials do not tell the full story; fight the urge no matter how bad you want to believe it.
-------
This is what I know at this moment. I don't know it all. Folk here are not shy to further clarify or to correct so be open to being wrong every once and a while. :razz:
If you want to still test for dissolved O2, then check out the Milwaukee manufacturer. Their O2 test is under $200 (usa) and I just recalibrate it once a month, sometimes more if I want to take the time.
------------------------
Be careful how many fish, especially koi, when dealing with a brand spank'n new water or after a very thorough pond cleaning. The water has to grow some algae or bacteria colonies for the nitrification process to remove the toxic Ammonia and Nitrites. Koi are well known to be heavy Ammonia producers. If ya want to learn more, then check out when to start adding fish.
-------------------------
I like the liquid test kits. I do not like the paper test strips since all they give is a "general idea" of something in the water. The electronic testers are expensive and require calibrations, sometimes often.
Love to ramble. So, in my rambling effort, hope it shines some light.
-------------------------
Good ya are being proactive about testing. My understanding is that most folk don't do it until there is a problem; honestly, by then, might be too late if ya don't like seeing death, when it happens, floating around in the water. From what I understand, extensive testing is mostly done by breeders, sellers, and avid hobbyists.
I enjoy being an avid hobbyist. I test for mostly everything, which is temperature, NH3 (ammonium, which is ionized ammonia), NH4 (unionized ammonia), nitrite, KH, GH, pH, nitrate, phosphorus, dissolved O2, salinity, total dissolved solids (TDS), and oxidation reduction potential (ORP). I only do the these tests once a week or bi-weekly, which take me between 30~45 minutes. There are more parameters such as copper, iodine, and others, but these "other" parmeters are mainly of concern to other areas such as maintaining reefs and aquatic breeders.
Primary tests, most Important. Temperature, ammonia (NH4 & NH3), nitrite (NO2), KH, and ((GH and pH if you have soft water )). To keep this brief, going to let my references, at end of my post, talk about the chemistry.
- Temperature : tells ya when to feed fish certain types of food and when to stop/start feeding fish. certain fish ailments can be fixed by water temperature.
- Ammonia (NH3) : safe form of ammonia to fish except temperature and pH will determine how much of NH3 will become the toxic, NH4, ammonia. Most Ammonia tests will combine NH3 and NH4 in the reading.
- Ammonia (NH4) and Nitrite : these two are very toxic to fish. these two will lower a fish's immune system making them more susceptible to ailments and death. Seachem provides a good liquid test kit to test specifically for NH4. Algae is also a plant that consumes ammonia directly, bypassing nitrification, so you may see an influx of algae of all types (string, floating, single cell) appear in the water.
- KH : buffers the lower spectrum of pH. if you have an acidic pH problem (that is below 7), most often it is due to low KH, called carbonate hardness. Soft water tends to have very low KH. If you are trying to use a pH down product or other acids, then the volume of KH will determine how much product will be required to lower the pH. The acids must first dissolve the KH; then, the pH will lower. Rain water is an example of water with very low KH; de-ionized reverse osmosis water has zero KH. KH is lowered with acids to dissolve the KH or by diluting the water with a more acidic, or softer water, such as rain or di-RO water. Also, nitrification will produce nitric acids that will slowly consume KH dependent upon the volume of Ammonia that needs to be consumed throughout the process. Nitrification is the process of bacterias and other organisms converting Ammonia to Nitrite then Nitrite to Nitrate then finally Nitrate to Nitrogen gas.
- GH : buffers the higher spectrum of pH. the higher pH will increase convert more NH3 to NH4. If you are adding Baking Soda to raise your KH, then your water could become very alkaline (pH 8 or above) if your GH is very low. Rain water tends to have lower GH; regular 2 stage reverse osmosis water (with a .1 micron filter) will have a very low GH. Various products can increase GH; beware, some products may increase salinity and, if ya ever have to treat your pond, then the salinity level will determine the effectiveness of medications. Fish need a healthy level of GH to help with osmosis regulation.
- pH : general indicator telling you if your water is acidic (below 7), neutral (7), and alkalinity (above 7). pH is determined by the volume and mutual exclusive relationship between KH and GH. "Total hardness" is a very vague test that tells ya how much KH and GH is available in the water. If your "total hardness" is low, then your pH will likely be more acidic.
Secondary tests. Nitrate (NO3), Phosphorus, dissolved O2, salinity.
- Nitrate (NO3) : Natural plant and algae fertilizer. At extremely high levels, nitrate will obstruct fish's osmosis regluation and retard the nitrification process causing a high volume of Nitrites.
- Phosphorus : One component consumed by algae when actively growing.
- dissolved O2 : nitrification and fish require a particular volume of dissolved O2 to survive. Temperature, heavy ammonia processing, algacides, and other medications can significantly change dissolved O2 volume.
- salinity : influences fish's osmosis regulation. It can force fish to build an extra coat of slime to fend of parasites, but also can lower the effectiveness of medications.
Other tests. total dissolved solids (TDS), and oxidation reduction potential (ORP).
- TDS : measures any particulates floating in the water. If you want to know how clear your water is, then do a TDS test. These tests can also be calibrated to be a salinity test.
- ORP : basically, measures the waters electrical charge in the water. this charge will determine how well particular oxidizers will work in the water. Salts change this chrage so ORPs can be calibrated to be a salinity tester. ORPs most often used when treating the water with medications that require a level of oxidization to be successful.
----------------------
I think this will give ya a basic start. Forum members here may likely have better references. Some of this stuff I use more as a guideline rather than a rule to follow.
What is the best way to lower KH and GH ?
Of course, we must talk about hardness
KH, pH, and don't assume everyth's ducky
Is it possible for Muratic acid to do some real damage while lowering pH?
Ammonia toxicity relationship to water temperature
(( grr, also have an article talking about how pH changes ammonia toxicity; sorting through my 50 or so unorganized bookmarks ))
Do fish drink? Fish osmoregulation and RO water
Soft water or hard water, which is best?
Adjusting KH and GH (( i just use this a general benchmark, I don't adhere to it 100% ))
When to start adding fish
Dissolve Oxygen water saturation levels for fish.
If all someone says is "it worked for me", then raise a skeptical eyebrow; often, something will "work" until it does not "work" so then it is changed so it will "work". Often, I have found out about this hobby, just like anything else, is that testimonials do not tell the full story; fight the urge no matter how bad you want to believe it.
-------
This is what I know at this moment. I don't know it all. Folk here are not shy to further clarify or to correct so be open to being wrong every once and a while. :razz:
Red Sea makes a marine and freshwater liquid test kit that cost a little more than regular liquid test kits for oxygen only. I have only used it once or twice, found I did not have to use it. but it nice to know when starting a pond. RDK
I have a waterfall so I guess I'm good to go, I'm not going to blow $200 at this point on that. The waterfall has been running for a week, I'm going to assume I'm good and once I've got all of the other pieces in place I'm going to move the fish. Thanks guys.
Waterfalls aren't generally very good for O2, better than nothing. For example directing the pump outflow to inside the pond instead of a falls will move more water, more stirring, more O2.
Keepers with high fish loads who worry about O2 don't generally measure O2 because it is such an expensive device and also because it doesn't do a lot of good. Good O2 right now can drop enough in a couple of hours to kill fish. So a good O2 reading doesn't really tell you much. Instead they focus on the things that keep O2 up like pumps, and on removing things that consume O2 like waste and plants.
Keepers with high fish loads who worry about O2 don't generally measure O2 because it is such an expensive device and also because it doesn't do a lot of good. Good O2 right now can drop enough in a couple of hours to kill fish. So a good O2 reading doesn't really tell you much. Instead they focus on the things that keep O2 up like pumps, and on removing things that consume O2 like waste and plants.
Well I'm adding a pump on the bottom of my pond as soon as it shows up. I have a skimmer box that will be on the surface and the pump attached to it will just sit on the floor blowing straight across the bottom. I'm expecting that will create a really nice circulation, but if not maybe an air stone. Doe air stones work by actually putting oxygen into the water or is it the same function as a pump? Just moving water to the top to get O2 at the surface?
crsublette
coyotes call me Charles
If ya want to make sure none of your fish die, then think about getting some Ammonia Binder chemical. Your Koi will produce ammonia, and if ya register any Ammonia and it is not noticeably reduced after 12 or 24 hours, then your fish's immune system will become weakened. However, for pH swings, not for sure on this one without prepping the water first. Just make sure ya do little water changes instead of big water changes. This can help reduce pH swings. If your water is really soft that has a low KH and/or low GH, then ya will need to do some research into this on how to raise it. Can do a quick forum search; good stuff here. 
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Yep, air diffusors just stir up the water moving the bottom water to the top. I have been told that the formation of the bubbles adds a little oxygen and this is why you want an air diffusor that produces many tiny bubbles instead of bigger bubbles; however, it is the bubbles pushing the water exposing it to the atmosphere, not the oxygen in the bubbles, that oxygenates water.
The same effect can be created with a fountain in the pond as well, but seems to me the air diffussors will stir up more water.
I think mainly cause I really like the tube air diffusors work better and they look pretty neat. Tube air diffusors push long wall of water instead of the air stones which just push water in a single column. However, I am told both are equally effective; to me though, it seems like the tube air diffusors work better by pushing more water instead of localizing the flow in a spot, but ya need a powerful aerator. I think a 1500 cu.in per minute aerator can fill a 3 foot long air tube diffusor with a good volume. I got the Hakko HK-25L hooked up to a T that feeds one 3 foot air tube and one 2 foot air tube; this aerator barely fills my 5 feet of air tubing with air, but it is still stirring up the water good from my perspective.
Honestly, I regret getting the Hakko since it only has one diaphragm. Eventually, the heat generated by the continuous aerator operation will add much weakness to the diaphragm causing it to fall apart, stop working. The diaphragm is what creates that strong air flow. If diaphragm gets worn out, then no more air so there are diaphragm replacement kits. This is why I should I bought an aerator that has more than one diaphgram; so, when one diaphragm gets burnt up, the other one will continue to operate, giving me time to replace the busted diaphragm.
For my qaurantine tank I got a 1/4" soaker hose. Going to see how this works. I am afraid it might product too big of a bubble. It would be neat though if it will produce tiny bubbles. Then, I could just put it in a wave pattern at the bottom of the pond.
The air diffusors moving the water will make it a little tougher for ya to see your fish since the surface is not very calm in the general area of the diffusor. This might be one reason why you would want to get one of the single column air stones.
-----------------------------------------
Yeah, I think O2 testing is more of a reactive test such as testing after water has been dosed with a product or if a person is just curious on the O2 content at the far end of a pond where water is not stirred well enough.
From what I understanding, oxygenating water is extremely easy to do with a simple air diffuser stirring up the water so O2 testing is not necessary ... unless you are concerned about a chemical or medication zapping the O2 content.
-----
Yep, air diffusors just stir up the water moving the bottom water to the top. I have been told that the formation of the bubbles adds a little oxygen and this is why you want an air diffusor that produces many tiny bubbles instead of bigger bubbles; however, it is the bubbles pushing the water exposing it to the atmosphere, not the oxygen in the bubbles, that oxygenates water.
The same effect can be created with a fountain in the pond as well, but seems to me the air diffussors will stir up more water.
I think mainly cause I really like the tube air diffusors work better and they look pretty neat. Tube air diffusors push long wall of water instead of the air stones which just push water in a single column. However, I am told both are equally effective; to me though, it seems like the tube air diffusors work better by pushing more water instead of localizing the flow in a spot, but ya need a powerful aerator. I think a 1500 cu.in per minute aerator can fill a 3 foot long air tube diffusor with a good volume. I got the Hakko HK-25L hooked up to a T that feeds one 3 foot air tube and one 2 foot air tube; this aerator barely fills my 5 feet of air tubing with air, but it is still stirring up the water good from my perspective.
Honestly, I regret getting the Hakko since it only has one diaphragm. Eventually, the heat generated by the continuous aerator operation will add much weakness to the diaphragm causing it to fall apart, stop working. The diaphragm is what creates that strong air flow. If diaphragm gets worn out, then no more air so there are diaphragm replacement kits. This is why I should I bought an aerator that has more than one diaphgram; so, when one diaphragm gets burnt up, the other one will continue to operate, giving me time to replace the busted diaphragm.
For my qaurantine tank I got a 1/4" soaker hose. Going to see how this works. I am afraid it might product too big of a bubble. It would be neat though if it will produce tiny bubbles. Then, I could just put it in a wave pattern at the bottom of the pond.
The air diffusors moving the water will make it a little tougher for ya to see your fish since the surface is not very calm in the general area of the diffusor. This might be one reason why you would want to get one of the single column air stones.
-----------------------------------------
Yeah, I think O2 testing is more of a reactive test such as testing after water has been dosed with a product or if a person is just curious on the O2 content at the far end of a pond where water is not stirred well enough.
From what I understanding, oxygenating water is extremely easy to do with a simple air diffuser stirring up the water so O2 testing is not necessary ... unless you are concerned about a chemical or medication zapping the O2 content.
I'll keep that in mind, I'm not worried about obscurring the view of the fish, there is enough surface area on the pond, if I obscur one area I'll just look at them in another area. No big deal. Plus I have a bridge, I could just put it under that, although I was thinking this would be one of their favorite hiding places, I don't want to make it too violent down there with churning water and bubbles.
crsublette
coyotes call me Charles
Bah, sorry, edited my post there about how to deal with the potential ammonia and pH swings. Ya were quick.
I am told fish love to do some body surfing in the bubbles. :razz:
I am told fish love to do some body surfing in the bubbles. :razz:
I used to think there was some gas exchange between the water and the bubbles. But now I think the atmosphere pressure inside the bubble is only a little less than the water pressure so there wouldn't be much gas exchange. But I'm still looking for a detailed source if anyone knows of any.
I would think the pressure of the water would win out over the atmospheric pressure in a bubble. I bet the air inside of each buble is worse, full of ammonia maybe, by the time it reaches the surface. Once it reaches the surface, there is no water pressure and the air pressure can do it's job. It seems very logical to me that it's just the circulation power that does all of this.
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from the net .........either true or false your choice
Aeration Technology
It doesn’t matter if an aeration system or device splashes, sprays, or diffuses air, the bottom line is how much surface area it creates. The surface area is where water contacts air and where oxygen transfer takes place. Smaller bubble size results in more surface area, which is why fine bubble aeration devices are superior in oxygen transfer than coarse bubble aerators.
Here is some more info on aeration and ponds............internet provided.
http://users.vcnet.com/rrenshaw/do.html
Aeration Technology
It doesn’t matter if an aeration system or device splashes, sprays, or diffuses air, the bottom line is how much surface area it creates. The surface area is where water contacts air and where oxygen transfer takes place. Smaller bubble size results in more surface area, which is why fine bubble aeration devices are superior in oxygen transfer than coarse bubble aerators.
Here is some more info on aeration and ponds............internet provided.
http://users.vcnet.com/rrenshaw/do.html
crsublette
coyotes call me Charles
Yep, sounds right Buckry since ammonia has the ability to degas. I bet ya will also find an amount of unbound CO2 mixed in with the O2 in the bubble as well. From what I've read, the ability of certain elements to degas is dependent upon water's pH.
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Heh, yeah, I have that article in my bookmark library as well. I thought it sounded familiar. It is where I was brought aware to the possibility that smaller bubbles oxygenates water upon the formation of the bubble rather than the actual air in the bubble.
The article also mentions circulation is important. In other words, the water is oxygenated in a general zone so if there is not a current then there will be water zones that will not be as oxygenated. I think this is one reason why tangential pond returns (TPRs) are very helpful since they help to create a water current in addition to help centralize debris collection for bottom drains and venturi valves help even more with oxygen.
Often, when fish swim under a fountain, near an air diffusor, under a waterfall, or gulping at the thin layer of water on the surface, this means they are needing to get a bit more oxygen in them so they go to the source for it.
"Dead zones" are created even in small bodies of water like ponds. Dead zones are created due to many variables such as algae, organic decaying, lack of current, nutrient pollution, etc. Dead zones are what creates all the nasty anaerobic stuff.
When ya go fishing, ya tend to only go to stagnant waters too catch catfish or even goldfish sometimes. Certain fish just do not need much oxygen in the water; this is why it is so easy to oxygenate the water for them since they do not need much.
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Welp, I tried the 1/4" soaker hose as an air diffusor. Boy, it works well. All sorts of very tiny bubbles. Also, it appears I am able to have a longer length air diffusor with the 1/4"; tested it out with 7 feet. Heh, cheap too.
-------------------------------------
Heh, yeah, I have that article in my bookmark library as well. I thought it sounded familiar. It is where I was brought aware to the possibility that smaller bubbles oxygenates water upon the formation of the bubble rather than the actual air in the bubble.
The article also mentions circulation is important. In other words, the water is oxygenated in a general zone so if there is not a current then there will be water zones that will not be as oxygenated. I think this is one reason why tangential pond returns (TPRs) are very helpful since they help to create a water current in addition to help centralize debris collection for bottom drains and venturi valves help even more with oxygen.
Often, when fish swim under a fountain, near an air diffusor, under a waterfall, or gulping at the thin layer of water on the surface, this means they are needing to get a bit more oxygen in them so they go to the source for it.
"Dead zones" are created even in small bodies of water like ponds. Dead zones are created due to many variables such as algae, organic decaying, lack of current, nutrient pollution, etc. Dead zones are what creates all the nasty anaerobic stuff.
When ya go fishing, ya tend to only go to stagnant waters too catch catfish or even goldfish sometimes. Certain fish just do not need much oxygen in the water; this is why it is so easy to oxygenate the water for them since they do not need much.
-----------------------------------
Welp, I tried the 1/4" soaker hose as an air diffusor. Boy, it works well. All sorts of very tiny bubbles. Also, it appears I am able to have a longer length air diffusor with the 1/4"; tested it out with 7 feet. Heh, cheap too.
Here's some things I've learned recently...
Water movement...
I've seen a couple of ponds using airlift pumps instead of water pumps to not just create current but to pump water above the pond surface. It kind of confirms to me that air is being used to move water. Smaller bubbles = more bubbles = more water moved. The bubbles work together so a million bubble spread out over a wide area do not move a lot of water.
Pressure...
The link above also said "Our concept was that fine bubbles will improve oxygen transfer to water being pumped" but they didn't really go any further on that. Their data was about bubble size and water movement. Nothing related to O2 transfer.
Air pressure in bubbles said the smaller the bubble the higher the higher the atmospheric pressure in the bubble. Confirmed by Laplace pressure.
Higher atmospheric pressure would force gases into solution. It seems to me, being unable so far to find an actual answer, that the pressure inside a bubble is higher than atmospheric pressure
I also found this in a PDF I couldn't get a link to.
So to me it sounds like air pump bubbles are higher pressure than atmosphere and so gases would be forced out of the bubble and into the water, but both O2 and C02. Seems to me that these higher levels would be at least a little bit temporary, that it's still the at the water surface that everything is going to even back out. For example, if you got the whole pond up to 10x max normal O2 that all that extra O2 would exchange at the surface and drop back down to max normal pretty fast. Like bubbles in soda.
If bubbles put more net O2 into the water it should also put more net C02 I think. But we do know that air pumps lower CO2 in ponds because we can measure increased pH level at least in low buffered ponds.
So, for today, I'm kind of back to thinking gas exchange at the surface is really the only important factor.
Ammonia is different
I've never heard, from either aquarium or pond keepers, anyone saying an air pump would reduce ammonia in any meaningful amount. They're only used to increase O2 in response to an ammonia problem to offset the fish reduced ability to use O2. Since ammonia is so easy to measure I assume if an air pump dropped ammonia amounts in meaningful amounts it would been well known. That's my thinking.
I have read (sources unrelated to ponds) that ammonia doesn't out gas very well at the levels we're concerned about in ponds. The lower the level of ammonia the less likely it is to out gas, and levels in ponds are very low from an out gas standpoint. Has to do with ionization. This is why water movement effects O2 and CO2 levels but not ammonia.
Water movement...
I've seen a couple of ponds using airlift pumps instead of water pumps to not just create current but to pump water above the pond surface. It kind of confirms to me that air is being used to move water. Smaller bubbles = more bubbles = more water moved. The bubbles work together so a million bubble spread out over a wide area do not move a lot of water.
Pressure...
The link above also said "Our concept was that fine bubbles will improve oxygen transfer to water being pumped" but they didn't really go any further on that. Their data was about bubble size and water movement. Nothing related to O2 transfer.
Air pressure in bubbles said the smaller the bubble the higher the higher the atmospheric pressure in the bubble. Confirmed by Laplace pressure.
Higher atmospheric pressure would force gases into solution. It seems to me, being unable so far to find an actual answer, that the pressure inside a bubble is higher than atmospheric pressure
I also found this in a PDF I couldn't get a link to.
So to me it sounds like air pump bubbles are higher pressure than atmosphere and so gases would be forced out of the bubble and into the water, but both O2 and C02. Seems to me that these higher levels would be at least a little bit temporary, that it's still the at the water surface that everything is going to even back out. For example, if you got the whole pond up to 10x max normal O2 that all that extra O2 would exchange at the surface and drop back down to max normal pretty fast. Like bubbles in soda.
If bubbles put more net O2 into the water it should also put more net C02 I think. But we do know that air pumps lower CO2 in ponds because we can measure increased pH level at least in low buffered ponds.
So, for today, I'm kind of back to thinking gas exchange at the surface is really the only important factor.
Ammonia is different
I've never heard, from either aquarium or pond keepers, anyone saying an air pump would reduce ammonia in any meaningful amount. They're only used to increase O2 in response to an ammonia problem to offset the fish reduced ability to use O2. Since ammonia is so easy to measure I assume if an air pump dropped ammonia amounts in meaningful amounts it would been well known. That's my thinking.
I have read (sources unrelated to ponds) that ammonia doesn't out gas very well at the levels we're concerned about in ponds. The lower the level of ammonia the less likely it is to out gas, and levels in ponds are very low from an out gas standpoint. Has to do with ionization. This is why water movement effects O2 and CO2 levels but not ammonia.