Tell me this is possible.

  • We are currently upgrading MFK. thanks! -neo
I've been using them for about 10 years. Mine aren't nearly as big though. Just long enough to go from tank to tank, where the tanks are almost side by side. It's a good way to give fish more space, without having one big tank. Also it allows you to have centralized filtration and do water changes for multiple tanks at a time. I got a 195g, 125g, and two 50 gallon tanks all connected together with these water bridges.

Some fish swim through them often and know their way around the tanks. They usually swim back and forth in the larger main tanks, but they'll go to 50 gallon tanks, which are planted, to look for snails/food to eat, to breed, and lay eggs, or sometimes just looking for a quiet place to rest (or die), away from the other fish.

Building them isn't too hard if you're good with DIY projects and have the tools and some shop space. You can make them out of acrylic sheet or PVC tubing. It's not cheap though.
 
Just build a sealed tube system and then draw all the air out of it. Think of it like turning a glass upside down in water and pulling it out. It is just a vacuum at work.
 
How do you suck the air out?

It's pretty simple. I put the water bridge exactly where I want it, where both ends need to be submerged underwater. Then stick some tubing up one end of the bridge. Then suck on the tubing to get the air out with either my mouth or a shopvac.

The waterline on both tanks needs to be same height also, else you'll siphon the water from the higher tank and overflow the lower tank.
 
How high up out of the water can it go? The one in the link looks super high. I have a door between my tank and where the second tank would go, so it would have to extend about four feet out of the tank. Is that too far?
 
How high up out of the water can it go? The one in the link looks super high. I have a door between my tank and where the second tank would go, so it would have to extend about four feet out of the tank. Is that too far?

It's not too far if it's built strong enough and supported correctly. There are probably better methods to build them than what I have done in the past. On my next builds, I may try to build them with plywood, FRP paneling, Fiberglass, epoxy resin, and glass. I want to build them so that they they have less reflective material on the inside so that the fish can swim/navigate through them better. Some fish will only swim in them at night when all the lights are off because they don't like the reflections. Sometimes the fish can't find their way out because of all the reflections. To some fish, it might feel like being in a maze or house of mirrors. I have painted the outside walls of mine, which helps a little bit, but painting the inside with something non-reflective would be even better for them.
 
Theoretically there is no limit to the height. It is a similar principle to you sticking your finger over a straw in your soda and pulling it out without spilling any soda. As long as pressure is equal on both ends there is no directional flow. This is basically how a lot of DIY overflows/continuous siphons work. Be warned, if there is a break in siphon on either end you are in for one heck of a mess.
 
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