# new level of High Tech? Oxygen injection?



## quark (Jan 10, 2014)

So I've had this crazy idea, maybe someone has thought of it too. Why don't we inject O2 like we do for Co2? Let me explain...

I've been battling algae in my 3.5 gallon iwagumi nano with mostly hair algae, and BBA. All seems to stem from a lack of Co2. I've managed to get my CO2 very high, in the 30ppm or above, I assume, yellow drop checker and gasping/stressed out fish, EI dosing is being done at a decent levels based on water tests, I still have extra's before a WC. Lights are at an estimated 40par or so.

I've started to add a cover to my tank, preventing fish from jumping, reduces surface scum, reduces evaporation, but also prevents gas exchange, CO2 is a bit higher, and O2 seems to be lower. Since agitating the surface of the water cause me to inject more CO2, why don't I inject O2 as well? Essentially saturating the water column with O2 and CO2 much like concentrations found in naturally occurring streams? without agitating the surface to cause a gas off? That means I can inject more CO2, and my fish would still be happy, and hopefully more plant growth, less algae.

Injection of the O2 would be from atmosphere air pump to a another diffuser or in my case a Rex Griggs reactor.

Thoughts?


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## Jeff5614 (Dec 29, 2005)

I'm sure others will chime in, but this has been the topic of a few threads lately where you can find discussion.


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## 691175002 (Apr 28, 2009)

There are several reasons why we inject CO2 but not O2.

The first is that the atmosphere is 21% oxygen but only 0.04% carbon dioxide. Because carbon dioxide is so rare (in a relative sense), the _only_ effective way to add more is by injecting it from a pressurized source.

There are numerous easy ways to increase oxygen concentration in the aquarium, although most of them come at the expense gassed-off CO2. One method that does not cause surface agitation is electrolysis (which directly converts the water into H2 and O2 gas). A commercial product that works using this principle is the twinstar nano.

Injecting atmospheric air into a standard reactor is unlikely to produce the results you are looking for, as the atmosphere is 78% nitrogen. Nitrogen has has an exceptionally low solubility in water, so the majority of the gas you pump into the reactor will never dissolve.

Frankly, I suspect that in most situations your best option is turning up the surface agitation and increasing CO2 to match. Tank refills are cheap.

Tom Barr has several posts on oxygen in the planted aquarium, as well as how to properly set up a wet/dry filter to increase oxygenation while maintaining CO2 levels.


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## quark (Jan 10, 2014)

Hmm...I must have not searched well, but most I see are about O2 and surface agitation. We all know that surface agitation is good for airating the water, but it also requires more Co2 Injection to be done, causes all other sorts of issues, evaporation, splashing, etc.

I'm talking about injecting it via a diffuser, just like how we do Co2, at first, my thought was through an air pump, but why not an O2 bottle? we can get O2 from welding supply. I'm pretty sure that dissolved O2 and Co2 in water at sea level is way higher than what could be achieved by injection, is my guess.

any chemist? physicists? enthusiasts?


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## Daximus (Oct 19, 2011)

quark said:


> ...Injection of the O2 would be from atmosphere air pump to a another diffuser or in my case a Rex Griggs reactor.
> 
> Thoughts?


A lot of people have airstones that kick on at night, same basic principle. Though I imagine an air pump, even a small one, without control (needle valve etc) would quickly overwhelm your reactor. 

Why don't more people do what your suggesting? 

If I had to guess...the results don't warrant the effort, as getting o2 into the tank isn't nearly as tough as getting co2. Cost-benefit analysis.


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## quark (Jan 10, 2014)

yes, wet dry filtration would surely raise O2 concentrations, but does require more Co2.

In such a small nano, it would have to be an external w/d unit, and sorta already have it in a pvc reactor. Good point though, need to figure out how to vent out the nitrogen, and thats were injecting O2 comes into play, no need to deal with the nitrogen.

Cost isn't a concern at the moment, getting a O2 tank and reg isn't much more than the co2 counterpart from like airgas. It would be welding grade Oxygen, but still good at somewhere around 99% oxygen, just don't smoke around your tank? :icon_eek:


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## KH2PO4 (Jul 18, 2009)

Tom Barr used to inject O2 (yep pressurized system). 
Now he doesn't, I remember he said there was no benefit.

Be aware that too high O2 can kill fish (Tom had warned about it too). 
It's called oxygen supersaturation, happens from time to time in nature:
http://www.startribune.com/local/east/234167401.html


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## JoeRoun (Dec 21, 2009)

*Some Mother's Children...*

Hi,

I use O2 injection for aquaponics, effectively keeping to many fish.

I use it in a couple of display tanks, same reason, though these are not planted tanks. 

While plants also benefit from good O2 levels, the principle benefit is to the filtration and well, oxidation of organic materials. 



This is the reason O2 injection is particularly beneficial to African cichlids and other high pH tanks where the total ammonia risk is greater.

The other thing about O2 is that a great deal of care needs to be exercised, the way I see planted tank types abuse and misuse CO2, the idea of O2 in the hands of folks that cannot manage CO2 scares me. CO2 injection is quite forgiving, O2 is not.


With O2 we not only have the opportunity to kill our critters due to the lack of patients and unwillingness or interest in following direction, but the risk to family and neighbors is very real.

Respectfully,
Joe
FBTB


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## mattinmd (Aug 16, 2014)

I'm certainly no expert, but a few things occur to me:

1) When the lights are on, and you are injecting CO2. However the plants, assuming the light is right, are going to be consuming that CO2 and making O2, and thus will raise the oxygen level. When your plants pearl it is because the O2 they are producing can't disolve because the water is gas saturated. If the plants are pearling, there's no point to injecting O2, as the water is saturated already. The best you could do is displace CO2 at that point.

2) At night when the lights are off, your CO2 may as well be off (or at least until just before lights on). At this point you could usefully inject CO2, but an air pump is much cheaper. Since the CO2 level is down, there's no real stress on the fish at this time anyway.

3) High levels of CO2 are dangerous regardless of oxygen levels. I can kill you by putting you in an atmosphere of 70% CO2 and 30% O2, even though the oxygen level is higher than the normal air you breathe. Living organisms must not only intake oxygen, they must also get rid of CO2 or die. High CO2 levels will stress out your fish, regardless of oxygen level, as it makes it harder for them to rid themselves of the CO2 building up in their systems. Yes, oxygen can help, but in part because it will displace the CO2 once the water saturates.


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## plantbrain (Dec 15, 2003)

Nano tanks have their own issues and keeping decent STABLE CO2 levels is not the easiest thing. Folks that tend their tanks and are good gardener's do okay. those who top off for evaporation often, keep their CO2 diffusers clean, allow ample plant growth and trim often as needed tend to do better. 

Since aquatic weeds grow fast, a small tank means they will grow very fast and top out on the surface in 2-5 days for many species. 

In a 40B, the same plants might take 10-14 days. 

So it's much less an issue as the tank gets larger.
Degassing rates change a lot as evaporation and current changes so rapidly.

I opt for non cO2 methods for smaller tanks personally, having had 8 nano's at one time, they are a PITA. Non CO2 is the bets method I would suggest for 5 gallon or less unless you have few other choices and are somewhat good at it.


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## quark (Jan 10, 2014)

High Tech nano tanks are indeed a PITA. my goal is to maintain this tank for at least a year, or till my next aquascaping contest at my LPS comes around next year.  Its a challenge I've accepted and determined to overcome. :thumbsup:

Guess my real reason for this was to avoid the surface agitation. If I could, I would seal up this entire nano tank in a controlled environment with a measured amount of O2 and Co2 being injected. I'm a control freak, and need to know everything in measurable terms. highly unlikely scenario though.



mattinmd said:


> I'm certainly no expert, but a few things occur to me:
> 
> 1) When the lights are on, and you are injecting CO2. However the plants, assuming the light is right, are going to be consuming that CO2 and making O2, and thus will raise the oxygen level. When your plants pearl it is because the O2 they are producing can't disolve because the water is gas saturated. If the plants are pearling, there's no point to injecting O2, as the water is saturated already. The best you could do is displace CO2 at that point.
> 
> ...


I'm no chemist, but I beg to differ. Plants pearl because they are producing oxygen at a faster rate then it can be dissolved into the water column. The reason it collects on leaves, is because of surface tension. Cut a stem of a healthy photosynthesizing plant, and tiny bubbles will float up, not because the water column has reached O2 saturation, but because the Oxygen is being produced at a faster rate then it can be dissolved into the water. I don't think we had reached saturation point, otherwise, there'd be no arguments about agitating the water surface during day time to introduce Oxygen in the water.

I think its about concentrations and percentages, high co2 is okay, as long as there is also high Oxygen to breath in the same breath, no? Do fish gills work the same?


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## JoeRoun (Dec 21, 2009)

*Look at the Pretty, Pretty Bubbles*

Hi,

No actually, CO2 and O2 in water are different from in the atmosphere. In truth in the atmosphere, mammals, birds and even insects are not okay with “high CO2” with “high O2.” Nevertheless, the rules for solvated O2 and CO2 and atmospheric gasses are different. 



Then the confusion of “bubbles,” oh well that is a whole other part of the story. However, with “pearling” you have inadvertently stepped into part of the difference. Any bubble you can see is of little or no part of the equation.


Fish gills, well fish are very different from mammals; mammals pretty much closed systems, limited entrances and exits.

Fish on the other hand are very (30% plus) open. When was the last time you peed (urinated) via your lungs, as a for instance.

Respectfully,
Joe
FBTB


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## roadmaster (Nov 5, 2009)

quark said:


> yes, wet dry filtration would surely raise O2 concentrations, but does require more Co2.
> 
> In such a small nano, it would have to be an external w/d unit, and sorta already have it in a pvc reactor. Good point though, need to figure out how to vent out the nitrogen, and thats were injecting O2 comes into play, no need to deal with the nitrogen.
> 
> Cost isn't a concern at the moment, getting a O2 tank and reg isn't much more than the co2 counterpart from like airgas. It would be welding grade Oxygen, but still good at somewhere around 99% oxygen, just don't smoke around your tank? :icon_eek:


 
Well if cost is not a concern,then wet dry filtration,or surface agitation(within reason), would only result in a bit more $$ of CO2.


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## quark (Jan 10, 2014)

Gosh, I'm going to have to be creative for a sealed wet dry filter for my 3.5 gal tank, mind you, it's in my office. 10 gallon sump? DIY bio balls in a PVC ?.......... Again, why not pressurized O2?


Sent from my iPhone using Tapatalk


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## mattinmd (Aug 16, 2014)

quark said:


> I'm no chemist, but I beg to differ. Plants pearl because they are producing oxygen at a faster rate then it can be dissolved into the water column. The reason it collects on leaves, is because of surface tension. Cut a stem of a healthy photosynthesizing plant, and tiny bubbles will float up, not because the water column has reached O2 saturation, but because the Oxygen is being produced at a faster rate then it can be dissolved into the water.


I said gas saturation, not O2 saturation. 

The amount of O2 you can dissolve in water is not independent from the amount of CO2 already in it. Water can only dissolve so much gas total.

Once you reach saturation, adding O2 is going to displace other gasses in the water, including CO2. 




quark said:


> I don't think we had reached saturation point, otherwise, there'd be no arguments about agitating the water surface during day time to introduce Oxygen in the water.


Personally, if your plants are pearling and thousands of small bubbles of pure oxygen are everywhere, I think the amount of oxygen added to the water by surface agitation introducing bubbles of air (<21% oxygen) is going to be small by comparison. 

Perhaps there's a mechanism I'm missing, but at the face of it, it looks absurd. Perhaps it depends on how much pearling we are talking about, but with heavy pearling you've got a whole lot of surface area being exposed to pure oxygen. 

I'd be more apt to suspect the benefit of surface agitation is to keep your CO2 levels in check and make it harder to gas your fish.



quark said:


> I think its about concentrations and percentages, high co2 is okay, as long as there is also high Oxygen to breath in the same breath, no?


No. As I already said, high CO2 is toxic in itself. Elevating the O2 won't save you from CO2 poisoning unless the CO2 is also reduced. 

Doubling the oxygen concentration doesn't double the amount of CO2 you can tolerate.



quark said:


> Do fish gills work the same?


Not in the general sense.

That said, I don't think that elevating dissolved O2 levels will save fish from elevated CO2 levels, unless it is by pure merit of the O2 displacing the CO2. 

Given the limited solubility of gas in water, this really could be a major limiting factor. ie: is it possible to dissolve a toxic dose of CO2 and double-the normal amount of O2 at the same time in water at the same time?


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## quark (Jan 10, 2014)

I've been thinking about this for quite some time, months, as you can see. I'm going to beg to differ here. Co2 and O2 concentrations in the water are independent of each other.

Increasing O2 concentrations does have a benifit if Co2 concentrations stays the same. If what I read is correct, fish expels Co2 based on concentration differences, meaning more O2 to Co2 levels.

I've search and search and Tom Barr's tanks constantly mentions about running sealed wet/dry filters to increase the O2 concentrations in the planted tank.

And thus, the lightbulb just hit, I already have a rexgriggs co2 reactor, why not run an air pump to it as well, maybe to start, just at night. The canister is sealed, so there would be no out gassing. Similarly to how the overflow intake of a wet/dry would suck the air down to the filter.


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## Raymond S. (Dec 29, 2012)

Don't know to what extent this is a factor to the person who would use the pressurized 
O2, but someone said it would be industrial grade Oxygen if gotten from a welding supply.
I used to work at an unnamed welding supply place and bringing the cylinders to the place to have them filled was part of my job.
They go on the same manifold that the medical Oxygen cylinders are placed on and are filled at the same time. The "medical Oxygen" status which claims lower levels of moisture are pure Horse feathers/cow poo. Just an excuse to jack the price.


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## exv152 (Jun 8, 2009)

Raymond S. said:


> Don't know to what extent this is a factor to the person who would use the pressurized
> O2, but someone said it would be industrial grade Oxygen if gotten from a welding supply.
> I used to work at an unnamed welding supply place and bringing the cylinders to the place to have them filled was part of my job.
> They go on the same manifold that the medical Oxygen cylinders are placed on and are filled at the same time. The "medical Oxygen" status which claims lower levels of moisture are pure Horse feathers/cow poo. Just an excuse to jack the price.


 The source of o2 is the same, that's a given, the difference is that medical and research o2 are guaranteed to be contamination free. The same can't be guaranteed with welding o2 due to the way the cylinders are filled, stored etc. 

Regarding o2, I was at Tom Barr's presentation at the AGA convention in Washington a couple of weeks ago, and he did a real interesting presentation about good o2, co2 and temperature in aquariums, which leads to high flux, good redox, healthy plant growth etc.


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## quark (Jan 10, 2014)

any chance that was recorded? Would have been interesting.


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## FlyingHellFish (Nov 5, 2011)

exv152 said:


> The source of o2 is the same, that's a given, the difference is that medical and research o2 are guaranteed to be contamination free. The same can't be guaranteed with welding o2 due to the way the cylinders are filled, stored etc.
> 
> Regarding o2, I was at Tom Barr's presentation at the AGA convention in Washington a couple of weeks ago, and he did a real interesting presentation about good o2, co2 and temperature in aquariums, which leads to high flux, good redox, healthy plant growth etc.


Moar!!! What did he do to raise the o2? I'm experimenting with super heavy filtration with no Co2, and some plants are doing great, others are "frozen" in time. HC has super compact small leaf size, great colour, just very little new growth.


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## quark (Jan 10, 2014)

HC is one of those that requires CO2 and high light to grow well. Given the Co2 and high light, the leaves pretty much double in size. I experimented with just light intensity and the more light, the bigger the leaves.

I believe in Tom Barr's tanks, he runs wet/dry filters with the filtration part, the part that drips, sealed off to the environment. This causes the ingested water/air mixture from the overflow to mix well, stay in a sealed wet/dry area, and then pumped back in. Pure O2 injection could be done, but I think he got very little effect on algae and plant growth.

I have a small 3.5 gallon tank I'm experimenting with, and a wet dry is going to be tough to do, only way I can simulate, is to inject air or pure O2 into my co2 reactor, which is sealed anyways. Thus oxygenating the water with air and pure co2, without the the surface movement.

In theory, this would produce a water with proper co2 concentration and rich in oxygen to support the fauna in the tank.


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## exv152 (Jun 8, 2009)

FlyingHellFish said:


> Moar!!! What did he do to raise the o2? I'm experimenting with super heavy filtration with no Co2, and some plants are doing great, others are "frozen" in time. HC has super compact small leaf size, great colour, just very little new growth.


What did Tom do to raise o2? He suggested avoiding surface scum at all costs. This prevents gas exchange between the water/air interface. That’s where a lot of o2 makes it way into the tank, and it has other benefits for the substrate too. Also, using a wet/dry filter, or sump, are really good for o2, in addition to good surface movement (not agitation, but just movement). And decreasing temperature slightly to like 25ºC. Kinda seems like common sense, but real interesting stuff. All plants will grow slower in cooler water, but maybe HC is especially susceptible to slower growth with lower temp.


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