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my dream indoor pond (video)
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alan
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Joined: 23 Nov 2007
Location: Grand Forks ND USA

PostPosted: 2007.12.02(Sun)18:39    Post subject: Reply with quote

fishy-frenzy wrote:

Is there any chance I could see a video or could you explain to me how it would fail?

In my opinion, and the videos I've seen already, I think it would work, as long as their is constantly a vaccum in the top, that keeps the water at that level.
!


2 things about the above:

First I checked but I think the clips I was sent have been taken off of YouTube for now.
They were only meant to be seen by me anyway so I understand them being gone now.

2nd, You use the word "vaccum" above.
and this is where I get tripped up.
I want you to look at the test I did in the kitchen sink with the beer drinking glass http://www.youtube.com/watch?v=jclt8nNOYM4 and think about this next question.

What if just before I tipped the glass up and trapped the air I also trapped a bee inside the glass?

Now I think that as the trapped air is still under normal air pressure the bee can keep flying around without a problem.

When I lift the glass up and the water inside the glass stays in position, I don't think there is actually a 'vaccum" suddenly is created in the top of the glass right?

I mean the bee does not suddenly get killed due to a loss of air pressure right?

so is there a true 'vacuum" in the trapped 2 inches of space?

This is a very important question for in the video test sent to me there is the clear suggestion that there is infact a true "vacuum" in the trapped space.
A true loss of norlam air pressure.
And as a little airpump needs normal air pressure to work, my idea about sticking a little air pump to the insides of the upside down aquarium falls apart.
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alan
Regulars


Joined: 23 Nov 2007
Location: Grand Forks ND USA

PostPosted: 2007.12.02(Sun)18:54    Post subject: Reply with quote

fishy-frenzy wrote:
Would floating plants be an option for the aquarium, or the pond?
!

plants or anything else inside the upside down aquarium is a danger because of the trouble they might be to get back out of there.

However the right plant inside the top of the aquarium might be one way to keep that air always fresh?

I just worry that once something floats up into there it's going to be work to clean it out.
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fishy-frenzy
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Joined: 30 Nov 2007
Location: Fort Worth, Texas, U.S.A.

PostPosted: 2007.12.02(Sun)20:05    Post subject: Reply with quote

Quote:
When I lift the glass up and the water inside the glass stays in position, I don't think there is actually a 'vaccum" suddenly is created in the top of the glass right?

In my opinion, I think that there is reduced air pressure, but not a complete vaccuum. The reason of this is because the water pulling down on it makes the air expand, and therefore result in the air having less pressure. If you were to add air into the aquarium, the pressure of the air would start to go back to normal, in my opinion. The goal is to find the right amount of pressure, to where the air pump would work in. If you first do as your video says with the glass, and then make the final touches by pumping the air out to where you want it, in my opinion this method will result in more air pressure than if you put the aquarium in the water and started by pumping all the air out. I have no proof of this, it is all in my opinion. Sorry I didn't make 'vacuum' clearer to you. Sad
Quote:
plants or anything else inside the upside down aquarium is a danger because of the trouble they might be to get back out of there.However the right plant inside the top of the aquarium might be one way to keep that air always fresh?I just worry that once something floats up into there it's going to be work to clean it out.

That is true, and if there is going to be plants underneath, you might want to weigh them down with something, so the koi doesn't uproot them Wink.

I don't have any more questions, so keep us informed. Smile
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alan
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Joined: 23 Nov 2007
Location: Grand Forks ND USA

PostPosted: 2007.12.02(Sun)20:41    Post subject: Reply with quote

fishy-frenzy wrote:
[In my opinion, I think that there is reduced air pressure, but not a complete vaccuum. The reason of this is because the water pulling down on it makes the air expand, and therefore result in the air having less pressure. Smile


This is at the heart of my problem understanding whats going on inside the glass in my kitchen sink, and in any pond tank I try to build.

Is the air pulling UP on the water?
Is the air pushing DOWN on the water in the glass?
Is the water pushing UP on the air?
Is the outside air pushing the water UP into the tank?

and...
Is there any difference in the nature of the "2 inch zone" when you get it via my way of just tipping the tank over trapping an air pocket, or when you get it via connecting an air pump and sucking out the air at the top?

The only way I know how I can find out the answers to such key questions is to build a life-size tank and do some experiments.

(Unless our interesting conversation has sparked the interest of a forum member who owns an empty aquarium/small air pump, and bathtub and who might want to do a test for themselves?)
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fishy-frenzy
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Joined: 30 Nov 2007
Location: Fort Worth, Texas, U.S.A.

PostPosted: 2007.12.02(Sun)21:49    Post subject: Reply with quote

Quote:
Is the air pulling UP on the water?

Yes, that is how I picture the air in the aquarium as doing.
Quote:
Is the air pushing DOWN on the water in the glass?

No, their is reduced air pressure in the aquarium, which results in the water staying up in the aquarium, and not sinking down. If the air was pushing down, their would be greater air pressure than the air outside the tank, and naturaly the air would want to equilize with the outside air, which would result in the water flowing out of the tank, and this is not the case.
Quote:
Is the water pushing UP on the air?

I'm not totaly sure what you're asking, so hopefully my answers to these other questions will answer this one as well. Sorry! Sad
Quote:
Is the outside air pushing the water UP into the tank?

Yes, the reduced air pressure in the tank results in the outside air wanting to fill that gap. Since the tank is underwater, the air pushes the water up the aquarium, and since the air cannot equilize, their is still some reduced air pressure, and therefore the water doesn't sink, and the air doesn't make it into the aquarium.
Quote:
Is there any difference in the nature of the "2 inch zone" when you get it via my way of just tipping the tank over trapping an air pocket, or when you get it via connecting an air pump and sucking out the air at the top?

In my opinion, trapping the air pocket will result in more air pressure than sucking out the air. This is because in the end you don't have to suck out as much air as you would when you start by sucking out all the air.
Quote:
(Unless our interesting conversation has sparked the interest of a forum member who owns an empty aquarium/small air pump, and bathtub and who might want to do a test for themselves?)

I might go and buy a 10 gallon aquarium. I already have a battery powered air pump, that I think would do a fine job. What do you think?

Any more questions?
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alan
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Joined: 23 Nov 2007
Location: Grand Forks ND USA

PostPosted: 2007.12.02(Sun)22:19    Post subject: Reply with quote

fishy-frenzy wrote:
[. I already have a battery powered air pump, ?

The danger part of my design is that I plan to use a real normal (plug in to the wall) type aquarium air pump.
this means that with my design I have to allow for the power cord to be under water. Thats no big deal for us today because many types of aquarium pumps and stuff run right into the water.

however to be safe I would go with a GFI type wall plug.
as for your battery powered airpump, I think that as long as the power of the pump is about equal to what a person would get from a wall powered pump, then the test would teach us much about the ability to have a "closed system"

Another darn problem we have to keep in mind however.
In my dream design, I have a upside down thin aquarium that sticks out of the pond about 2 feet.
This hight has to be taken into account.
This hight might add some unknown presure onto the air trapped in the aquarium.

what I have been thinking about for doing a full-size test is this:.
There is a store here called TJ MAX, where they sell lots of different types of glasswear.
I once saw at TJ MAX a glass jar that stood about 3 feet tall, yet was a round cylinder only 8 inches across.

I will check around to see if TJ MAX has more such stuff.
For such an item would allow me to do a full-size test of my design and have the hight sticking up above the pond water level that I plan for my final tank/pond design.
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alan
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Joined: 23 Nov 2007
Location: Grand Forks ND USA

PostPosted: 2007.12.02(Sun)22:31    Post subject: Reply with quote

Powerhead test?

I do not own a Powerhead, but I have a question about how they work.

As far as I know, the powerhead type water pump , pumps water very fast, and that there is an air hose that connects to it and draws air down to the Powerhead where it's mixed with the water...Correct?

My question is this.
Most photos and video I have seen where a Powerhead was being used to draw in air from the top of the aquarium, the Powerhead was always located very close to the top of the aquarium.

Could a powerhead still draw as much air if you placed it on the bottom of an aquarium?
Would the amount of sucked-in air become less the deeper you positioned the Powerhead in the aquarium?

If you had a real deep aquarium of around 3 feet tall, and had two powerheads running, one just at the top of the aquarium, and the other all the way down at the bottom, would the top one be blowing more air bubbles than the bottom one?

the reason for my question is very important.
This is because I have been sent another video where a guy used a powerhead to show me that as the hight of the water inside the upside down aqurium goes up, the ability of a Powerhead to draw air goes down and then stops.
The results of this video test hint that my idea of glueing an air pump inside the upside down aquarium will fail because as the water level goes up the pump stops working.

However in the video test I noticed that what was also happening is that the powerhead was actually getting deeper and deeper away from where it was drawing air from inside the upside down aquarium.

If the ability of a powerhead to draw air changes in any way with the depth you position it at, then the video test is in error and my idea can work.

if the ability of a powerhead to draw air does not change when you lower the powerhead deeper into the aquarium, then the video test is correct and my idea may never work!
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