Never, Ever, Remove Your Airstone...

[umpsfar]

I'm hard pushed to accept Sooo many experts are saying no to air depletion.
i would be inclined to agree with mr hensonc4098.

before i got the spraybar we sometimes lifted the back lid up and move the water output a few inches higher when the fish are gasping, after a hour or two they would return to normal breathing.
i have my spray bar going off now for 15 minutes every 2 hours from morning till night.
i picked up one because my filter had lost its power to break the surface of the water (i needed to clean it) at the time and the fish where gasping like they had done the 200 metres..
Its a tall 145 litre and its my girlfriend who reminds me i have turned the spraybar timer off when she notices the fish suffocating.

so,,, Fish gasping for air, lethargic, depressed looking.

"spraybar on" or water output tube lifted higher up so bubbles go into the tank.

fish perk up in 10-30 mins.

im not in the humor for strangling my fish to prove me right, all i see is cause,effect, solution.

sorry for your deaths hensonc4098,

 

[three-fingers]

If turning your airpump off leads to the fish being deprived of oxygen, then all that means is that you have too many organisms living in the tank for the given surface area and/or the temperature is too high.

Airpumps just circulate the water a little bit (not nearly that much compared to a water pump) and make the surface of the water ripple - increasing the surface area for oxygen to move into the water and reach it's equilibrium level (which will be higher the lower the water temperature is).

Given the presence of nitrite, I'm going to have to say that's why the fish died. Nitrite severely affects fishes gills ability to take in oxygen.

So really, turning off an airpump is no problem, and airpumps should never really be necessary unless they are powering a filter or in an emergency. They can look nice, but IMO if you think you need one to provide oxygen for the fish, you should look at reducing your numbers of fish.

 

[keenonfish]

What form is your filtration? Are you using under gravel filter or a small power filter?

Also, another thing with stocking levels is that CO2 from fish builds up if the surface area is not large enough to cater for the number of fish in the tank (thinking specifically the hex here). Just maybe the water agitation was enough to keep co2 levels in check previously?

 

[aaronnorth]

if you think you need one to provide oxygen for the fish, you should look at reducing your numbers of fish.

or increase surface agitation with the filter.

this is just one of those conincidental things me thinks,

 

[GAB99]

they were suffering because they were used to all the extra oxygen. when you suddenly turned it off they couldnt handle it.

like a like a smoker trying to quick cold turkey.

it would be better if you got live plants and started to lower the amount the airstone is used unti you can safley turn it off without them gasping for air


personally i never got an air stone because to me it just looks dumb,reminds me of the little mermaid

this is my own thinking as i have never had an airstone and my fish are not suffocating. plz no flaming

 

[Curiosity101]

Water can only have a certain level of oxygen dissolved into it due to surface agitation.
It's not as if the water went from super high oxygen to super low oxygen (like a smoker quitting smoking).
Thats a silly statement.

It's (as said above)
A) Trucks explanation (which I personally think had an affect)
AND
B) The filter isn't placed suitably to give enough agitation of the surface. If filter + air pump gives enough agitation then the filter alone should be able to as you can only ripple the same surface area.

I have managed to swap from air pump to no air pump with NO affect to my fish. They showed no distress...no gasping...no deaths.
I simply turned off the pump and adjusted the filter output to compensate. Simple.

Also any toxins (ammonia or nitrite) that was present in the water can and will cause gill damage, meaning you need a greater concentration of oxygen in the water OR a large volume of water/great surface area.

 

[Tolak]

If you pulled the air stone, and the filter didn't cause enough surface agitation to keep the O2 level high enough for the stock in the tank you will have an O2 depletion problem. This is the biggest problem when there is a power failure with overstocked tanks, temperature and bi filtration will often be fine for several hours. A few hours with no surface agitation & the O2 level drops.

I have a couple of tanks, overstocked as usual, which have canisters as the main filters. I also will run sponge filters for starting up new tanks in with the canisters. When I pull the sponge filters, which agitate the water the same as an air stone I have no problem, as I do make sure the output of the canisters agitates the surface really well.

right....seeing as you disturbed the substrate, you more than likely disturbed some anaerobic bacteria...when the bacteria comes into contact with oxygen it goes through a chemical reaction where the hydrogen sulphide that is in the anaerobic pockets take on oxygen to create sulphur dioxide

this will have more than likely depleted the tank of oxygen

This is interesting, and something I had never thought of, the dioxide component being implicated in lowering the O2 level. Having mostly bare bottom tanks it is something I would likely never encounter.

 

[Bignose]

If it is a hex tank and tall like most hex tanks, I suspect that the air stone was helping circulate the water more than anything else. As was posted above, the bubbles themselves add almost no oxygen to the water. It isn't because the bubbles are "too large", it is simply a matter of time. There isn't enough time that the bubble is in contact with the water to transfer any significant amount of gas.

But, what an airstone does do, is that as the bubble rises, it drags water around it up with it. This helps recirculate the water. It brings the water at the bottom up the top where it will take in oxygen from the surface and since it is a closed system, as some water comes up some other water must go down. Specifically, the water from the top, that was just oxygen enriched now goes down to the bottom. Overall, the oxygen level is increased because of the increased mixing.

I would also agree that since this seemed to happen so quickly, that the stocking levels probably do need to be reexamined. Problems should not have occurred that quickly.

 

[Nick16]

As was posted above, the bubbles themselves add almost no oxygen to the water. It isn't because the bubbles are "too large", it is simply a matter of time. There isn't enough time that the bubble is in contact with the water to transfer any significant amount of gas.

surely then it is to do with bubble size, over time in the water bubble size decreases (its how bubbles work in the sprio diffusers) therefore its a combination of the both. Having smaller bubbles would help as they would diffuse into the water better (i use a diffuser instead of an airstone and that does the job perfectly, small bubbles that barely reach the surface)
it must be a combination of both factors, one cant be dismissed.

 

[matchstickman47]

i found you dont need airpumps 4 planted setups and seriously do what every1 else says n get a spraybar

 

[yabadaba]

I bought an airstone for my 2ft tank when I got a Hillstream Loach, as I'd heard they demand well oxygenated water. I tested my water before adding the airstone and it was at the maximum staturation level during the day, but it was a fair bit lower first thing in the morning. After adding the airstone it has always been at maximum saturation 24/7. To be honest this did surprise me as the tank is probably over-filtered with a Fluval U3 and I'm using the upper outlet so there is a lot of surface agitation. To be honest I suspect my tank is overstocked, which might explain that, but given that the Rena air pump is virtually silent and that adding the airstone has definitely resulted in an increased level of oxygenation, I have left it running. The overstocking will be remedied as soon as my new 5f tank has finished cycling.

But, the other reason why I leave one in the tank is that my cory's just love playing in the bubbles - in fact they'll soon be moving to the new tank so to keep them happy I've just ordered another pump and airstone!

 

[DiscusKeeper403]

Not sure if this has been said, but you definitley need something for surface agitation or most fish won't be able to hand the lowered D.Os in the water. From my understanding, when people say not to use air pumps it's because they have a filter creating surface agitation anyways.

 

[Bignose]

As was posted above, the bubbles themselves add almost no oxygen to the water. It isn't because the bubbles are "too large", it is simply a matter of time. There isn't enough time that the bubble is in contact with the water to transfer any significant amount of gas.

surely then it is to do with bubble size, over time in the water bubble size decreases (its how bubbles work in the sprio diffusers) therefore its a combination of the both. Having smaller bubbles would help as they would diffuse into the water better (i use a diffuser instead of an airstone and that does the job perfectly, small bubbles that barely reach the surface)
it must be a combination of both factors, one cant be dismissed.

In an old thread, I did some calculations: http/www.fishforums.net/index.php?showtopic=66913

Even really small bubbles, 3 mm in diameter, you only get 10^-10 g of oxygen (0.000 000 000 1g) from each bubble as it rises -- and that's only in water completely devoid of oxygen. Real water will always have some oxygen in it to start with, limiting even further how little oxygen really gets transferred.