How'd they do that?


New member
I have seen that article before and thought it was pretty interesting. It would suck to have that vacuum broken somehow and have water gushing out of those holes....messy


Premium Member
The overhead is nothing really complicated, but the feeding holes are mind boggling. How did they do that?


New member
There is no headspace in the tank, and no air gap at the top. It is completely sealed all the way around, except at those feeding holes. I don't know if they actually pull a slight vacuum. The space for the feeding holes are relatively small. For water to gush out the feeeding holes, air/water would have to retract inward at another hole, but the balance of pressure won't allow that.


New member
Must be perfect balance, surface tension not broken by fish feeding either. I'd imagine like stevereino said, must have some vacuum, air bubbles up there could be devastating. pretty awesome. where is it?


In Memoriam
my guess they could enrich the water being filtered with o2 or by it just passing thru the bio filter might be enough to keep them breathing


In Memoriam
i thought about that last night as long as you suck out the air at all times you would be good

but on a side note what are the metal screws made out of?
also allot of water on the floor :)


New member
<a href=showthread.php?s=&postid=11667284#post11667284 target=_blank>Originally posted</a> by Caragol
That tank reminds me of this one posted here a while back:

I would really really love to know how it's done and if it's sustainable for long periods of time without worrying about disaster.

That one I think I get... My guess -- Even though he's calling it a closed system, it's really not. If you look at some of his other vids, you can see one that shows a hole in the side of the tower, just below the water level of the lower tank. He started off with a small volume of air in the top of the tower. He has a vacuum pump connected to the top of the tower that will constantly pull air out. As the air is pulled out, the water is sucked higher into the tower, lowering the level of water in the lower tank. When the hole is exposed, air bubbles enter the tower and rise to the top, displacing water which then covers the hole again. The airstone we see in the video is a negligible amount of air compared to the capacity of the vacuum pump. I think the vacuum pump must have some check valves if he said power outages are no problem...

The one Jeni posted is a lot more complex, I think.