External Aeration ?

Hello!

I have done lots of research online and I cannot find what I have in mind so I am resorting to here for some ideas before I build something myself.

I am aiming for an aquarium where all of the important components are external to the tank.
I want to achieve this without a sump.

Here is my setup from top to bottom.
I have a 55 GAL freshwater aquarium and I run a canister filter.
I have multiple canisters, each with a different purpose, hooked up in series, to be specific.
To give you an idea, it's something like this;
There's a Pre-filter canister (3 tier mechanical sponge) connected to a Top Fin CF60 Canister filter with quartz-bio media in the center connected to another canister filled with Coral Sand (for PH buffer) connected to another canister filter which acts as a fluidized moving bed filter using BioBalls which then is connected to an external water heater before being returned to the aquarium.

That all sounds overly complicated when typed out like that but I enjoy building these things.

What I am looking for is something I can hook up in series to my system that, for lack of a better name, is an external aerator.
I understand that with enough surface agitation the water will be aerated and I can easily continue using an air stone, that is beside the point.

My initial design thought are basically a container with an air stone inside where the water can flow in, move across an air stone and flow out.
I want the water to flow out without solid bubbles, only the dissolved oxygen, in it so the bubbles don't shoot out of my water return.

TLDR: Want to build or buy an aeration device that is not inside the tank without using a sump.

Any thoughts or suggestions are appreciated.

Thanks.

 

This a rough first draft idea of what I am thinking.

 

Am I just crazy?
I suppose the invention of such a device is pointless being as its much easier to aerate from within the tank.

 

No you're not crazy. Couldnt you modify a powerhead...supply hose to the bottom and output connected to a hose inline to aerate your setup?


Or maybe something like this

 

That sounds like it would work.

I'm going to mock up a design that uses a container, an automatic air release valve, and an air stone to oxygenate the water without having any bubbles visible from the viewing pane.

If I have any success, I will post pictures.

 

You might be able to use a protein skimmer made for saltwater.

 

I found this on Ebay.

 

Airstones do not, by themselves, increase dissolved oxygen in the tank. The bubbles they create don't dissolve into the water at all. They work by agitating the water and therefore increasing gas exchange. So the device you're thinking of will not actually increase oxygen levels in the water.

The best way to increase oxygen in your tank IMO is by adding lots of plants.

However, if there is enough water movement, your tank likely has more than enough oxygen in it already, unless there's a reason you didn't mention that you think low oxygen is a problem.

 

Airstones do not, by themselves, increase dissolved oxygen in the tank. The bubbles they create don't dissolve into the water at all. They work by agitating the water and therefore increasing gas exchange. So the device you're thinking of will not actually increase oxygen levels in the water.

The best way to increase oxygen in your tank IMO is by adding lots of plants.

However, if there is enough water movement, your tank likely has more than enough oxygen in it already, unless there's a reason you didn't mention that you think low oxygen is a problem.

Airstone do, increase surface area contact with air, and thus increasing gas solubility of oxygen.

The rate of gas transfer, Jgas (mol gas mol−1 water s−1), is defined by Fick’s law and is proportional to the product of the total interfacial contact area (A, m2) per unit system volume (V, m3) and the concentration gradient (to convert to the more common unit of molar concentration in mol l−1 s, one can use the conversion factor of 55.6 mol water l−1). For gas absorption, the concentration gradient is the difference between the saturation and existing mol fraction of dissolved gas (Xgaseq−Xgas), yielding Fick’s law in the form...

https://ascelibrary.org/doi/10.1061/(ASCE)EE.1943-7870.0000943

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3673973/


The bubble dimensions are calculated using processing[/URL] techniques. The results show that bubbles of smaller size from smaller nozzle for a fixed superficial gas velocity with maximized surface area, take more time to reach the surface, increasing the residence time of each bubble in the water, allowing a better oxygen transfer rate.

 

Does the phrase "needlessly complicated" sound about right?

I'm concerned with the "automatic air release valve". How will that work exactly? The drawing as shown will have water pumping out under pressure through the air valve, rather than being pumped up to the tank. How would you overcome this basic problem?

 

The aI'm is to have extremely small bubbles already in the water of my filter return. If that requires something "needlessly complicated" then so be it.

The way an automatic air release valve works is a pretty basic concept, if you take a look at the in the link below you will understand.

 

The aI'm is to have extremely small bubbles already in the water of my filter return. If that requires something "needlessly complicated" then so be it.

The way an automatic air release valve works is a very basic concept, if you take a look at the in the link below you may understand.
https://sdt.com.vn/dzung/PLAST-O-MATIC/Air release valves working principal.gif

That is a pretty slick and simple design. Is clogging typically a problem? Maintenance?

I guess I am not following correctly. I thought you were trying to avoid releasing the bubbles into the tank, rather than having that as the goal.

 

No, you are correct.
My original idea was exactly that, to introduce air into the system without a seeing a wall of bubbles.

I am hoping that with the device that I purchased that the bubbles will be extremely small and I think that I can live with that.

I will let you know how maintenance goes.

I build some prototypes of the original plan but could not get it to perform as intended.
If I had access to a 3D printer then I most likely would have more success.

 

The diffuser came in the mail yesterday, the one in the link below, and I hooked it up to my system.

At first there were some larger bubbles in my return but within an hour the bubbles were so fine I could barely see them.

It works perfectly for what I wanted and will seamlessly integrate once I hookup my CO2.



The product is really high quality!