# Aeration



## raze (Jan 29, 2015)

Hi guys,

On my 650 litre tank I was told that if I set up my internal filter to make the top of the water a little wavy that this would be enough for aeration. I am going to be putting in an airstone on a air pump in anyway but I am curious on your thoughts.


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## Mcdaphnia (Dec 16, 2003)

That is a sort of modern half myth. It is not false, but not entirely accurate. If the surface of the tank is rippled, it has higher total surface area and more surface means a larger area for gas exchange between air and water. However airstones, air operated sponge filters, and Jetlifter operated Mattenfilters can move and mix substantially more air and water. A saltwater wholesaler inadvertently demonstrated dramatically this while setting up his new fish room. The blower was oversize to allow for the next expansion, and the effectiveness of air in saltwater due to the smaller bubble size was not taken into account. It was turned on full power to the tanks. In seconds over 2000 gallons of new saltwater was on the floor and a couple hundred aquariums were about half empty of water.


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## The Cichlid Guy (Oct 18, 2014)

My filter outputs are angled towards the surface, as is my powerhead. I don't care for the appearance of bubbles underwater, so I've never really used an airstone.

It's hard to say whether or not aeration is sufficient, because it can't be measured. But I would say the majority of us aren't using bubblers, with no ill effects.


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## joescaper1 (Feb 14, 2013)

I personally do not use an air pump with a stone( it costs money I don't believe I need to spend). However, I like the bubbles in the water, so I use the air infuser on my power heads with the directional pointed downwards. It does roil the water surface. I have noticed evaporation is considerably more in the tanks employing this technique. I have read on some posts that air constantly in suspension is harmful to fish; but if that is true, no fish would ever be at the base of a waterfall or dam, and I know that is not true.


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## nodima (Oct 3, 2002)

I've not used an airstone in my tanks in years. They are definitely not needed as long as the surface is able to be reasonably wavy. Generally the filter returns on my tanks are set up across the top of the tank, just under the water line. This way there is no splashing, but plenty of surface agitation. That said, my two big tanks also use sump filtration which causes additional aeration to occur.

I've seen mention of micro bubbles being blamed for fish dying, but I've never seen anything more official than internet discussion of it, so I tend to doubt it occurs, and rather something else is wrong and the bubbles taking the blame.

Bottom line IMO, air stones and pumps are not necessary, but if you like how they look they are not harmful either.


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## Mcdaphnia (Dec 16, 2003)

nodima said:


> I've not used an airstone in my tanks in years. They are definitely not needed as long as the surface is able to be reasonably wavy. Generally the filter returns on my tanks are set up across the top of the tank, just under the water line. This way there is no splashing, but plenty of surface agitation. That said, my two big tanks also use sump filtration which causes additional aeration to occur.
> 
> I've seen mention of micro bubbles being blamed for fish dying, but I've never seen anything more official than internet discussion of it, so I tend to doubt it occurs, and rather something else is wrong and the bubbles taking the blame.
> 
> Bottom line IMO, air stones and pumps are not necessary, but if you like how they look they are not harmful either.


One of the nice things about airstones or air operated sponge filters, is that whether they are in a tank or not, being able to add them at an instant's notice when stress or a new problem is observed is very helpful, and can be done at the same time as an extra partial water change.

Ripples on the surface increase the rate of evaporation but not as much as using air does. Possibly that evaporation rate is also an indication of each method's relative effectiveness. Bubbles can be messier, leaving moisture on the underside of tank lids, and mineral spots on equipment near where the bubbles burst. Sumps, wet/dry filters, calcium reactors, and protein skimmers (mostly used in saltwater, not fresh) are very effective at adding oxygen to the tank. A bubble-less, ripple-less, non-electric method to keep the oxygen level in a tank at maximum is a Soechting Oxydator. This is a device that has a reaction chamber that catalytically converts hydrogen peroxide into oxygen before introducing it to the tank water. However it is a device rarely if ever available outside Germany so it is not a viable alternative to 90% of the world.

Micro bubbles are a problem in saltwater and reef tanks. The surface tension of salty water (and sewage water) is different from fresh and causes the propagation of much smaller air bubbles than using the same device in freshwater. Try it with an air stone, fascinating. The micro bubbles can get trapped in the tissues of live corals and even in fish. Mazes and other devices capture the micro bubbles before the filtered water is returned to the aquarium. If freshwater had micro bubbles in it, it would have become so saturated with either salts or organic waste that the surface tension of the water was changed. Those salt and waste levels would probably kill freshwater fish before the micro bubbles had a chance to.


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## nodima (Oct 3, 2002)

That all makes sense, Mcdaphnia - the point about evaporation is a good one with one caveat - generally a filter return is not aimed upward enough so that it splashes water uncontrollably, which is what bubbles do. I've noticed bubbles much smaller in SW but did not know the underlying factors enough, and your post would reinforce my thought about bubbles being wrongfully attributed in a FW system.


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## Mcdaphnia (Dec 16, 2003)

If you want to control the air bubbles, a lift tube called a Jetlifter is very effective at releasing the bubbles horizontally. Or you can use a tee on top of a regular lift tube. Attach a riser tall enough to let the bubbles burst inside it.


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## Mcdaphnia (Dec 16, 2003)

Microbubbles in freshwater don't seem possible to me from an air stone. Tap water in winter can get very cold and absorb more air. It's pressurized inside plumbing and when placed directly into an aquarium, bubbles form. They can have the same bad effects as saltwater microbubbles. Aeration will speed the removal of these bubbles.


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