Air driven over the tank filter.

[m1ste2tea]

Until it doesn't, at which point having a single source of oxygen (or rather, lack of it) is a quick and easy way to kill off a tank.

I'm all for effeciency and minimising operating costs, but not to the point that this becomes a higher priority than those they serve.

If power goes out then either way you're screwed unless you have a backup power source, if you're referring to a malfunction of the mechanisms, id place my bet on an air driven pump rather than an impeller driven one, since there is less of a chance that it would get jammed, less moving parts, and less tendency to overheat.

 

[Egon]

Until it doesn't, at which point having a single source of oxygen (or rather, lack of it) is a quick and easy way to kill off a tank.

I'm all for effeciency and minimising operating costs, but not to the point that this becomes a higher priority than those they serve.

LOL That's just like saying the glass will hold the water........"until it doesn't"

Or how about this one: The wings will lift the air plane "until it doesn't"

A catastrophic failure is bad no matter which piece of equipment fails. Heaters, pumps, the tank glass............

 

[Egon]

I should add that this will create a rather small amount of waterflow no mater how much air you are pumping, however you are definitely aerating the water this way and can have this setup as the only aeration system, thus eliminating the need for another appliance using electricity, I have had a similar DIY system running in one of my tiny fry tanks for a while now. It works.

I disagree with this statement and most likely I'm wrong so help me out with my reasoning on this one.

I think the air pump system creates a very large water flow but is most effective on deeper tanks. Also very little head, basically the water will not rise very much above the surface level of the tank. The filter mechanism needs to be inside the tank like the ray tank link. The water is pulled through vertical tunnels in the back of the tank. Water flows up one tunnel with an air stone placed directly under it. Wafer flows down another tunnel with a venturi effect. The water serpentines through up and down tunnels and gets filtered. I think this is the best system for very large tanks because compressed air is very cheap and very easy to work with/regulate. Simple backup systems can made to keep air flow constant and consistent. It's really a very smart and simple system.

Next statement I disagree with and I apologize, I'm not trying to put anyone on the spot. It's always been a misconception that air stones in a fish tank add O2 to the water. The air stone agitates the surface of the tank causing oxygen to be absorbed into the water, the actual air coming out of the air stone does not dissolve into the water. A power head churning up the surface of the tank would yield the same results.

Anyway my .02 all comments are welcome and I could be

 

[m1ste2tea]

Egon, lets see... you propose that this would work better if the mechanism is placed deeper in the water, this is true... only if the pump is sufficient enough to pump the air into the deeper water, definitely no wimpy air pumps allowed. so the deeper in the water it is the more pressure that pump will have to work against. however that pressure can work to your benefit, because it will also want to fill the void left by the air saturated water more vigorously, and thus will work better this way. thus it can be said that this sort of mechanism of moving water is directly related to the depth of its placement.

your second point is also agreeable, it is indeed a common misconception of airstone providing oxygen, its what happens at the surface that really aerates the water, be it air bubbles or a powerhead. the nice thing with an air stone is that it will do the job no matter where the placement is.

keep the $.02 coming

 

[Braddo]

I am wanting to test a theory i have for air driven lifts. My plan works the way you sugested on suctin rather than pushing. I am going to test by using 20mm pvc one end in a bucket the other in a tank on the top level of a 4 tank tier. The end in the tank will have an U shape with the airstone in the outlet for the tank. My hope is that it will suck the water from the bucket into the tank if it works I will then add it to a couple of tanks on a small system. So it will over flow into the filter and suck back up the pvc to the tank. You should be able to control the water flow by the amount of air running through the out let.
Hope that makes sense.
In a room like mine with 100 tanks I run a system but still have air running through the tanks to create better circulation through the tanks. So I have a water pump and air pump running would be great if I could cut it down to just the air pump which uses 180watts of electricity compared to 400 watts on the water pump.

 

[Egon]

I am wanting to test a theory i have for air driven lifts. My plan works the way you sugested on suctin rather than pushing. I am going to test by using 20mm pvc one end in a bucket the other in a tank on the top level of a 4 tank tier. The end in the tank will have an U shape with the airstone in the outlet for the tank. My hope is that it will suck the water from the bucket into the tank if it works I will then add it to a couple of tanks on a small system. So it will over flow into the filter and suck back up the pvc to the tank. You should be able to control the water flow by the amount of air running through the out let.
Hope that makes sense.
In a room like mine with 100 tanks I run a system but still have air running through the tanks to create better circulation through the tanks. So I have a water pump and air pump running would be great if I could cut it down to just the air pump which uses 180watts of electricity compared to 400 watts on the water pump.

I'm looking forward to what you find out.

 

[m1ste2tea]

The end in the tank will have an U shape with the airstone in the outlet for the tank.

sounds good braddo. just make sure that the bottom of the U shape is as deep as possible to get the most suction force out of the airstone, which has to be located right after the U shape tube makes the turn around the bottom. Is the bucket that its sucking water from on the same level as the top teir tank or is all the way at the bottom? It may not be enough suction if the water has to climb a 6 foot head. Im interested in the results nonetheless, if you can save that much wattage it would be great.

 

[Braddo]

I will be testing the bucket on a few different heights this will give me some idea how to approach the set up. I did visit a gold fish farm once that had it using air to push the water. But it used similar to the ray tank with 90mm pvc piping and airlines attached all the way around the complete diameter. It flowed like a guiser to just over half a foot above the ponds.
I am thinking the same about the amount of suction but it is worth a try.