Air Stones....

[DevotedToDiscus]

so I can't put the air stone in the overflow? Man, that really sucks, Right now I have one air stone turned on, on the side that the filter is not on so that way there is a calm side and a current side, it seems that my fish like it this way, but I'm going to try and put together your tube and see how they like that, they seem to like the flow of the filter only. Thank you for your help! It is much appreciated!

I can't say yes or know, without really seeing it. Try it and see how it looks....you should get a good idea if it looks like it is aerating the water well or not. Your fish will soon tell you if they need more oxygen, as they will all be up at the surface.

 

[ian]

an airstone alone isn't needed. They are purely for aesthetic use, as for aeration, your filter outlet should provide all the aeration you need. DTD's idea is a better idea, this way the O2 will dissolve...just be aware if you're running a planted tank without pressurised C02, you may drive the C02 off out of the water, in turn leaving your plants wanting.

Airstones IMO are very 80's

 

[Baccus]

I have airstones in my tanks and have found they are great for stopping the temp in the tanks from getting way over heated in our Summer heat and humidity (the tanks have been hovering around 30degrees C for the last couple of weeks ) also my cory's love swimming in the bubbles and often lay their eggs on the glass behind where the bubbles from the airwond is. I also have another smaller stone at the opposite end of the tank in a fairly heavily planted corner which the plants seem to like and helps to stop that corner accumilating junk from the rest of the tank. On the tanks that have airstones I am running them on multi-valves so I can individually adjust the bubbling rate and slow it right down if necessary.


And nothing wrong with the 80's .

 

[raptorrex]

I wanted to see what people thought of Air stones, I have 2 in my tank, I love the look of them but I am not sure they are doing much good, I have a 60 gallon semi-planted tank and I think they are just causing too much current. Also wanted to know if fish can survive without them or is it their main source of oxygen? I'd like to do away with them but I'm not sure if I can. Would my fish survive with a filter alone? If so should I raise the filter to oxygenate the water? Someone please advise me!!!

there is no need for an airstone.. MOD EDIT
I use them, and always have, but only for aesthetics.
honestly, if your tank NEEDS an airstone. you are doing something, very, very wrong.

if you are interested in the maths (around O2 absorption) Bignose has written an interesting post. and provided ample evidence, if any were needed!

airstones and aircurtains are great, just dont fool yourself they do anything but look good.

this said, i use the flow caused by them, to draw heavier waste to the back of the tank. there it is either picked up by my filter. or removed with a gravel vac.

 

[snazy]

I really get confused with the airstones being for aesthetic reasons only.
If the filter does not do good water surface movement, then you need something to additionally move the water surface of the tank as that's where the O2 exchange is created.
So whether you use a more powerful air pump or powerhead/filter for that it don't matter, it just depends how much it moves the surface and the tank setup and fish preference.
People suggest addding an airstone when medicating, but yet people say it does not add oxygen. So this is quite contradicting.

Also my understanding is the process of air/water exchange at the surface also adds all other type of gases in the water like O2, CO2, nicotine smoke, etc.. Or does this process extracts/breaks only the oxygen from the air? Maybe because there is more oxygen than CO2 in the air, that's why the prevalent gas that enteres the water is oxygen? Anyway, adding oxygen won't displace the CO2 directly so fish can still die if CO2 is injected artificially in big doses.

I have 2 setup tanks at the moment, one without airstone, but the spray bar is creating loads of water movement and surface movement and I haven't had a problem with the fish. However, there are no plants in this one.
The second tank has an air pump rated double the amount of water volume for the tank, 2 filters and good amount of plants. I was worried that the guppies had too much current in the tank and reduced the flow of the air pump only to find them next morning gathering at the surface, so air pump is back to normal flow now. My plants are not growing super fast, but are healthy looking and doing well without CO2 added. I don't even use ferts, but will try the Flourish Excel staff once it arrives. Of course, the plants are not high demanding ones that need too much, but still...
I was also reading about the Walstad method of planting aquaria, based on Diana Walstad reseach, in which no CO2 injection, air stones and even water changes are needed at all. From what I can gather, different type of bacteria in the fish tank produces CO2 and minerals when conditions are favourable(subtrate is not very compacted let's say and fish waste is left to dissolve, rather than being siphoned out in order to be used in the process). Then the plants in turn use the minerals to grow and produce oxygen needed for the fish to thrive. Very interesting read, not sure whether I can do it right though.

Sorry for the long reply. I guess it contains more questions, than answering anything

 

[fishguy2727]

As stated I have seen air stones alone save many tanks many times when the filters stop running for no reason. To me that is more than just looks.

Yes, a filter should provide more than enough aeration. But I prefer to have more than just enough. Many fish enjoy the bubbles, that alone should be reason enough to provide them. Saving an entire setup when the filter that was providing all the aeration stops for one reason or another (which definitely happens) should also be more than enough reason to run one.

I have also seen many tanks have more flow created by the air stones than by the filters, both HOBs and canisters. A good strong air pump can create a lot of very natural flow. A HOB, canister, powerhead, etc. create a lot of flow in a small area or stream but fail to get the entire water column moving. Air stones can get the entire water column moving.

This is what I have posted before on this subject and I will post it again here for anyone interested:

Bubbles actively aerate the water. Gas exchange occurs at ANY air-water surface. The oxygen doesn't stop and think, 'Hey, this is just a bubble, I can't cross here, I have to wait until I am in the air above the water.' This is well known and accepted in other industries, but for some reason it just can't seem to catch on here (maybe because none of us are professionals, just hobbyists, regurgitating what we hear other hobbyists claim?). Bubble aeration is a strong tool in both aquaculture (real aquaculture, not hobbyist aquariums) and sewage treatment because the bubbles themselves actively aerate the water column.

I have seen multiple tanks saved multiple times simply because they had an air stone. I have seen tanks that started losing fish within only a couple hours of a filter stopping because they had no air stone.

The only hope someone has of proving the idea that bubbles don't aerate is showing that there is a minimum reaction time required between the air and water for aeration to take place. IF this were true then that would also apply to water flow at the surface of the tank. If there is a minimum reaction time then strong flow at a tank's surface would inhibit aeration by not allowing a long enough reaction time between the air and the water quickly flowing by. Since I think we can all agree that is not the case, then it should be apparent that bubbles themselves do actively aerate. Smaller bubbles create a lot more surface area per volume of air. Larger bubbles have less surface area per volume of air but create more flow than smaller bubbles. Both can greatly increase overall aeration in an aquarium.

The basic assumptions/issues in question are:
1-Bubbles add little surface area
2-They rise too quickly for aeration to take place

1-Every single bubble is a sphere of surface area. With a strong air pump and fine bubbles you can actually match and exceed the top surface area of the tank. Any surface area counts. The surface area in bubbles does not collect a film that inhibits aeration the way the surface of the tank does, so it has the most potential for aeration. Because the bubbles are moving they are constantly exposed to water that has less oxygen than the water they had just been exposed to, meaning the potential for aeration is very high (like the cross current flow of blood in fish gills).

2-Bubbles do not rise too quickly for aeration to take place. This would require there to be a minimum contact time between air and water for aeration to take place, which is not the case. Aeration is diffusion, gasses passing from air to water and from the water to the air, and this takes place almost instantly. More contact time increases it, but there is enough contact time for aeration as bubbles rise to the surface. If this were not true, if there was a minimum contact time, then it would be possible to have TOO MUCH flow at the surface of a tank because the water would simply pass by the surface too fast for aeration to take place. This is obviously not the case.

So an air stone doesn't aerate just increase flow? Then I guess too much flow in a planted tank will also drive off CO2?

In the end I don't know what people think they are gaining by arguing against this so hard. It is a cheap piece of equipment that could potentially save every fish in someone's tank some day. Why make an issue?

 

[raptorrex]

As stated I have seen air stones alone save many tanks many times when the filters stop running for no reason. To me that is more than just looks.

Yes, a filter should provide more than enough aeration. But I prefer to have more than just enough. Many fish enjoy the bubbles, that alone should be reason enough to provide them. Saving an entire setup when the filter that was providing all the aeration stops for one reason or another (which definitely happens) should also be more than enough reason to run one.

I have also seen many tanks have more flow created by the air stones than by the filters, both HOBs and canisters. A good strong air pump can create a lot of very natural flow. A HOB, canister, powerhead, etc. create a lot of flow in a small area or stream but fail to get the entire water column moving. Air stones can get the entire water column moving.

This is what I have posted before on this subject and I will post it again here for anyone interested:

Bubbles actively aerate the water. Gas exchange occurs at ANY air-water surface. The oxygen doesn't stop and think, 'Hey, this is just a bubble, I can't cross here, I have to wait until I am in the air above the water.' This is well known and accepted in other industries, but for some reason it just can't seem to catch on here (maybe because none of us are professionals, just hobbyists, regurgitating what we hear other hobbyists claim?). Bubble aeration is a strong tool in both aquaculture (real aquaculture, not hobbyist aquariums) and sewage treatment because the bubbles themselves actively aerate the water column.

I have seen multiple tanks saved multiple times simply because they had an air stone. I have seen tanks that started losing fish within only a couple hours of a filter stopping because they had no air stone.

The only hope someone has of proving the idea that bubbles don't aerate is showing that there is a minimum reaction time required between the air and water for aeration to take place. IF this were true then that would also apply to water flow at the surface of the tank. If there is a minimum reaction time then strong flow at a tank's surface would inhibit aeration by not allowing a long enough reaction time between the air and the water quickly flowing by. Since I think we can all agree that is not the case, then it should be apparent that bubbles themselves do actively aerate. Smaller bubbles create a lot more surface area per volume of air. Larger bubbles have less surface area per volume of air but create more flow than smaller bubbles. Both can greatly increase overall aeration in an aquarium.

The basic assumptions/issues in question are:
1-Bubbles add little surface area
2-They rise too quickly for aeration to take place

1-Every single bubble is a sphere of surface area. With a strong air pump and fine bubbles you can actually match and exceed the top surface area of the tank. Any surface area counts. The surface area in bubbles does not collect a film that inhibits aeration the way the surface of the tank does, so it has the most potential for aeration. Because the bubbles are moving they are constantly exposed to water that has less oxygen than the water they had just been exposed to, meaning the potential for aeration is very high (like the cross current flow of blood in fish gills).

2-Bubbles do not rise too quickly for aeration to take place. This would require there to be a minimum contact time between air and water for aeration to take place, which is not the case. Aeration is diffusion, gasses passing from air to water and from the water to the air, and this takes place almost instantly. More contact time increases it, but there is enough contact time for aeration as bubbles rise to the surface. If this were not true, if there was a minimum contact time, then it would be possible to have TOO MUCH flow at the surface of a tank because the water would simply pass by the surface too fast for aeration to take place. This is obviously not the case.

So an air stone doesn't aerate just increase flow? Then I guess too much flow in a planted tank will also drive off CO2?

In the end I don't know what people think they are gaining by arguing against this so hard. It is a cheap piece of equipment that could potentially save every fish in someone's tank some day. Why make an issue?

if you are not looking after your tank, PROPERLY, you may well need an airstone.
however for those who do (look after their tank properly) airstones are for looks, and current. as far more o2 is, far more effectively, absorbed through surface interaction.

 

[snazy]

however for those who do (look after their tank properly) airstones are for looks, and current.

Just out of curiosity, can you elaborate on what proper looking after a tank is?
Seems I have a problem as without the air pump set on high the fish started gasping in the morning. I would love to know how to fix that as I am sick of looking at the tubes running in.

 

[fishguy2727]

Are you running CO2 at night? Check your nitrite in the morning. If something is off nitrite can cause them to gasp too.

I am not sure what that poster meant by not taking care of an aquarium. Any well maintained tank can have the filters stop for no good reason (cichlids spit sand in filter intake, impeller breaks or wears out, pump finally fails, etc.), in which case an air stone alone could save everything.

In general, as has been stated, proper filtration should provide more than adequate aeration. It is when something unexpected happens that air stones can make all the difference in the world for your fish.

 

[KISSfn]

I have one because my fish enjoy it and it looks cool!

 

[Lufbramatt]

In my experience a well maintained filter will last for years or decades even (i still have a 25 year old eheim internal that works fine, afaik its still got the original impellor in it). air pumps are notoriously unreliable as nearly all aquarium air pumps rely on a flexible diaphragm to pump the air which degrades and splits in a relatively short period of time. I wouldn't rely on an air pump to save my fish, I run two external filters instead, anything that will take both of them out at the same time (ie a power cut) will take out an air pump too.

 

[fishguy2727]

There are air pumps that have built in battery backups.

Even without that, most filters last nowhere near 25 years, especially with the original impeller. Filter failures can occur for many reasons (fish spitting sand in to intake, impeller breaking or dying, filter pump dying, etc.), any one of which can remove all aeration provided buy that filter. IME air pumps require no maintenance and last years without even having to touch or think about them. You may have to replace the actual air stone from time to time. But for their cost they are more than worth it.

I think for those who have not experienced a filter failure like that it may seem too rare to worry about. I have been in the pet industry for ten years and have had and seen the experiences of myself, my customers, and my service clients. I have seen it too much to risk it with my own tanks or ask anyone else too. I hope those who don't see the risk never have to experience the loss it can create firsthand and learn the hard way.

 

[TwoTankAmin]

This is not an easy topic to research. I just spent the last 90 minutes surfing through Google Scholar looking for a definitive answer. The one thing I found that seems relevant came from here http/cefas.defra.gov.uk/publications/troutnews/tnews35.pdf#page=24

Bubble diffusion, which is used widely on fish farms, is not as efficient as the surface agitators. This is basically because the depth normally encountered in inlet channels or fish tanks are often too low, 1-1.5 m, for efficient uptake of oxygen. If depths were higher, 3-3.5 m, diffusion can be quite efficient, even more so than surface agitators.

This is not a research paper, so one can attack the conclusion based on that. However, since it involves business and making fish farming efficient, it certainly appears credible from that point of view. What it indicates is that for most of the aquariums used by fishkeepers, airstones etc. are not nearly as effective as surface agitation because bubble aeration needs more depth than will be found in most tanks.

The one fact that seems to be accepted in all the research I looked at was that finer bubbles are more effective than larger bubbles at diffusing oxygen in water.

 

[fishguy2727]

What it means is that you need more air stones than just the one. This creates more air bubbles = more aeration. It is not that there is a minimum depth for the aeration to take place, just that in a shorter depth there isn't enough of it to exceed what can be done with surface agitators. So it is happening, but if you are trying to aerate a small lake there are more effective methods.

Yes, smaller bubbles create more surface area per volume of air = more surface area for aeration to take place.

Thank you for the research.

 

[coldcazzie]

Just a reminder: please remain civil while discussing this topic. People are allowed to have differing opinions, and provide evidence to back up their views, but we will not tolerate posts which are disrespectful.