Need instructions on how to create a water bridge.

[gwand]

I would like to create a water bridge to join two 5 gallon aquariums that will permit fish to transit back and forth to both tanks. How do I create water flow in the bridge tunnel if it is elevated above the tanks? I can’t break the laws of fluid dynamics.

 

[TwoTankAmin]

I think you will have problems doing this with such small tanks. But here is a decent vid on how to build the bridge. If you are familiar with how an overflow works for an un-drilled tank with sump filtration, you will understand the principles involved.

 

[MaloK]

If you pump water from one tank to the other the equalization between them will make a siphon creating movement in the bridge.

 

[Oldspartan]

If you pump water from one tank to the other the equalization between them will make a siphon creating movement in the bridge.

I am trying to picture this in my mind. Wouldn't the connection require the water in the feeder tank to rise above the rim? Am I being dense? (probably)

 

[MaloK]

That's the beauty... It cant. As soon as the water level lowers it draws from the bridge to level on the other one.

Of course you can override the bridge by pumping more water than it can move...

But, both tanks will have the exact same level of water all the time in normal conditions. They are now the same body of water.

Removing a cup of water from one will draw 1/2 a cup from the other.

Put that cup in the thank you removed it, how much water moves to the other tank ? another 1/2 cup.

 

[Magnum Man]

using a pump, to start the draw, to fill the bridge is genius...

 

[MaloK]

I installed a PVC bridge between 2 betta tanks once... It took some time, but when they met, it became hilarious.

Short story long.
Once one had the courage to go up the tunnel and found the other tank. he thought he found paradise... 1 minute later he was fleeing from where he came. The owner didn't pursue in the tunnel, but made it a chore to surveil the newly found entrance. While the other hid in his tank for a couple days.

Then with time both became bolder but always respected the tunnel as the territory limit, still couldn't resist stepping on the others grass on regular basis.

They played cat and mouse like that for a while and one funny thing that happened is one day I came to the tank and they had switched side...

I felt like I had missed something.