[natebuchholz]

It is impossible. Water follows the path of least resistance. The water in the "bridge" would flow to either side and overflow either or both of the tanks beside.

You could connect them directly like this. [_]=[_]

 

[ChappyEight]

Nate, thanks for your input. However, the water will stay in the bridge and will not overflow (yay science!).

Here's a good explanation: https://youtu.be/1tmsHa5spqc?t=512

 

[Frozenguy]

It works fine.

Once you stick a tube up in the bridge, and suck the air out, water will be pulled up and held in place by vacuum.

Go to a sink full of water, put glass in water and fill. Then tip upside down and pull the cup out without letting the rim break air. The water stays in the cup.

Bump: If you have air in your system, even micro bubbles you can't see, they could have a tendency to collect in that bridge. It wont destroy the vacuum, it will just increase the water level in your main tanks. So this is an added maintenance you have look out for.

I would recommend making the inlet/outlet of the bridge long enough so you can tip the bridge up sufficiently to drive air bubbles up to a corner to suck out.

current will be almost non existent and driven by temperature difference. Something to consider.

You could pump water easily from one tank to the other tank. As you pump water from tank on the left, and increase on the right, it will be equalized via the bridge by flow. The flow might be low so matching flow of the pump might have to be considered.

Btw, Cool Dad!

 

[Vidikron]

Nate, thanks for your input. However, the water will stay in the bridge and will not overflow (yay science!).

Here's a good explanation: https://youtu.be/1tmsHa5spqc?t=512

Based on what he said at the end of the video about the water levels equalizing between the tanks I'd be inclined to try a canister with the intake and return in different tanks. That way you would be ensured that water is moving through the bridge. With two filters I would be concerned that you might not get much movement through there. Sounds like fun project. Post pictures when finished!

 

[ChappyEight]

Vidikron, I'm right with you. As of now, I think that's what I'll do. Probably go with a Fluval 206 and a 200w inline Hydor heater.

Hoping to pick up the glass next week.

 

[Mariostg]

It will be perfectly ok, unless there is an air leak in the bridge. Or atmospheric pressure is different on each tank... kind of unlikely.

Thanks to Mr Bernoulli and his fluid dynamic work.

In fact it's just like an HOB. When your turn the pump off, if the u-shape tube touches water on both sides (filter, tank), water level will equilibrate.

 

[Immortal1]

Very cool idea. I would go with the canister filter and have the intake in one tank and the return in the other tank. Fish being curious (at least my panda garra's are) I'm sure they would use it. This is a cool idea, unfortunately for me, I am trying to keep the "left" fish tank fish our of the "right" fish tank

 

[Mariostg]

Fishes that like current could have lots of fun in the bridge.

 

[Raymond S.]

I am concerned about the glass tops. Water may hold via condensation to those tops and "wick" over the top edge. E-bay sells plastic clips which enable you to hang a glass top
inside of the tank. Don't know the complications which will result from the "other than" square shape of the top. The clips are meant for cube aquariums to be able to have a glass top. Rimless tanks that is.
I think the pick up in one tank and the return in the other tank/w a canister is what you will need to insure good filtration.

 

[PlantedRich]

A couple small thoughts. One thing is the way air will collect in the bridge. It will ease the problem of removing it if you do have a slight tilt to the top. either by cutting the sides somewhat less than true flat or by lifting one end. Either way will make the air collect at the end where it is easier to suck out.
But when fish are added, they are pretty likely to use the bridge but there is often a small hicky to the plan. They like to go upstream and all the fish may tend to wind up in one side. Some may stay in the bridge but you may want to plan in a way to occasionally reverse the flow through the bridge. A canister filter will tubing that was easy to swap the intake/output might work well.

Congrats on spending some time/effort for the kids!!!!

 

[schnebbles]

RCS would most likely be eaten by a betta. My betta hates everything. He's mad right now at some little horned nerites I put in there. All depend on the betta - I used to have them in community tanks but now i have a hateful one!

 

[DaveK]

Vidikron, I'm right with you. As of now, I think that's what I'll do. Probably go with a Fluval 206 and a 200w inline Hydor heater.

Hoping to pick up the glass next week.

I know others suggested this arrangement, but it's got one big flaw. If the bridge ever fails you will have a major flood on your hands. Consider too how this will be in a 4 yr old's room and how at that age they tend to mess with things. oops.

I would put a small hang on tank filter on each cube, or also do a tank to tank level connection, so that if the bridge fails, you will not have a flood.

 

[Hoppy]

If the bridge isn't attached to the tanks, a curious person (child?) may pick it up to see what happens. With that big a bridge, what happens wouldn't be pleasant. Also, if nothing unpleasant happens immediately, the filter would soon pump all of the water to one side with the overflow ending up on the floor. If the bridge is attached to the tanks, someone (adult) may decide to use it to lift the tanks. That will almost certainly ruin your day. Finally, keeping the bridge inside surfaces clean will be enough to make you wish you weren't so creative!

 

[keymastr]

With the intake and return in different tanks you will have a problem with removing debris from the tank the return is on since that tank has no intake you will be relying on debris flowing up the bridge tube. In fact there may not be enough flow in the intake tank to push debris towards that intake either. Should be a fun experiment though.

I would spend the cash and have the tanks and bridge built out of acrylic if it were going in a child's bedroom. That will be a scary amount of glass.

 

[ChappyEight]

I am concerned about the glass tops. Water may hold via condensation to those tops and "wick" over the top edge.

Great point. I'll grab the clips on eBay.

One thing is the way air will collect in the bridge. It will ease the problem of removing it if you do have a slight tilt to the top. either by cutting the sides somewhat less than true flat or by lifting one end. Either way will make the air collect at the end where it is easier to suck out.

Great thought. With dirted, I'll get bubbles pretty often so this is definitely something to consider.

I know others suggested this arrangement, but it's got one big flaw. If the bridge ever fails you will have a major flood on your hands. Consider too how this will be in a 4 yr old's room and how at that age they tend to mess with things. oops.

I would put a small hang on tank filter on each cube, or also do a tank to tank level connection, so that if the bridge fails, you will not have a flood.

Thanks Dave. However, aside from catastrophic seam failure, any leaks will actually leak air into the bridge, not water out of the bridge. Also a good thought on my daughter messing with it, but it's pretty much out of her reach, and she and her brother help me take care of the 36g and know not to touch. Still, a good thought, thanks.

...keeping the bridge inside surfaces clean will be enough to make you wish you weren't so creative!

Haha, this made me chuckle. You're right, it will be a bit more difficult, but with a magnetic scraper each week I hope to stay on top of it. If it ever gets really bad, I can always remove the bridge and spray it out with the hose during a water change (i do 50% changes).

With the intake and return in different tanks you will have a problem with removing debris from the tank the return is on since that tank has no intake you will be relying on debris flowing up the bridge tube. In fact there may not be enough flow in the intake tank to push debris towards that intake either. Should be a fun experiment though.

I agree, that could be problematic. I'm a weekly water-change guy so hopefully the frequency of wc's will prevent this from being an issue.

-------------------

Thank you all very much for chiming in. I'm excited to get going and will definitely be heeding your advice. Like I said, I hope to get the materials to start next week. The pace will be controlled by the budget.

God bless.

 

[Aquatic Delight]

you mentioned you do 50% water changes......how will that work with this bridge? will you have to recreate the vaccum every time you do a water change?

for that matter how do water changes work when you have a bridge?

 

[DaveK]

...
Thanks Dave. However, aside from catastrophic seam failure, any leaks will actually leak air into the bridge, not water out of the bridge. ...

Once you break the siphon, you create a flood. It's a lot easier than you think. Any air getting insider will get trapped. The size of the bridge generally prevents any bubbles from flowing through. I hate to sound all "gloom and doom", but I have seen this sort of thing many time with external overflows on SW reef systems. One "major manufacturer" has a notorious reputation for their overflows failing because they tend to trap air. I think your really looking for a stomping doing this.

As a general question to others, who has has actually installed a large bridge like this and had it function for a long period of time without a failure and flood?

 

[PlantedRich]

If the bridge extends down far enough into the tanks so that the water level stays above the lower end, there is no problem with water changes. Just have to stop draining before that point is reached. Draining out of one side will only make the water run from the other thank, through the bridge into the tank being drained. No problem. Running a filter sucking water out of the left tank will lower the level only a small amount if the filter and flow are somewhat right.
For cleaning the bridge, the magnet scraper does most of the work but since they are not able to get fully into the corners, a scrap of rag will stick out to get most of the cleaning done. If some really rough , hard stuff gets on the inside of the bridge, a piece of string and a rag solves it. Push the string through, tie the rag on and "saw" it back and forth in the corner where the cleaning is needed. This is the way to clean hard stuff out of filter tubing if a brush doesn't get it. I'm betting on the OP to be able to see a clear path on things!
I didn't find the price of glass vs acrylic enough to go with glass. This is not a project to worry too much the cost as it is not something that can be "justified" on any level of practical use. Much cheaper than buying an I-pad and serves much better purpose?

Bump:

Once you break the siphon, you create a flood. It's a lot easier than you think. Any air getting insider will get trapped. The size of the bridge generally prevents any bubbles from flowing through. I hate to sound all "gloom and doom", but I have seen this sort of thing many time with external overflows on SW reef systems. One "major manufacturer" has a notorious reputation for their overflows failing because they tend to trap air. I think your really looking for a stomping doing this.

As a general question to others, who has has actually installed a large bridge like this and had it function for a long period of time without a failure and flood?

This is where the user has to do a bit of figuring!!
On the flooding point, it is simple to make the amount of water in the bridge less than the amount of open space in the tanks. If you lose suction totally, the water runs into the open space in the tanks.

How long to actually use one? About 6 months. I needed to move and the guy buying the house paid at least three times the value for me to leave it!

Interesting project but once done it was not that interesting to rebuild.

 

[GraphicGr8s]

What you want to do is nothing new.

http://www.aquariacentral.com/forums/threads/diy-water-bridge.70053/page-4

http://weburbanist.com/2008/12/27/aquariums-fish-tanks/

Rich were you the one that did one out of clear pvc?