Water Bridge flow rate?

[Quatro]

Hey,

does anyone know how to calculate the maximum flow rate through the bridge in a setup like this?  http://www.bio-elite.com/waterbridge.htm

Thanks

[Contains Moose]

I would think it should be the same as a siphon drain,maybe not, what size pipe?

[Quatro]

I believe they are using 4" pipe.  I am trying to do something similar (but with bulkheads) to connect the tanks to a central filter.  I also use strainers so the fish can't cross it.  I did my first water test last night and the water hardly flowed at all.  I am using 1" pipe and got maybe 30gph.  Also the water level in the first tank ended up being much higher then the second.

[Hookup]

without a differential between the two systems the flow rate will be effectively 0gph.  If you use a pump, and overflow to create a differential then the water will flow.  At that point you'll know your flow rate based upon however you create the differential.

[RossW]

No. I pump water out of my one tank through an external canister filter and into the other tank. Gravity keeps the water level of the two tanks the same and there is constant motion of water through the tunnel. It also keeps the chemistry of the water in both tanks the same. If your filter pumps 2000 liters of water an hour; this is the volume of water that passes through the bridge every hour

[Contains Moose]

I believe they are using 4" pipe.  I am trying to do something similar (but with bulkheads) to connect the tanks to a central filter.  I also use strainers so the fish can't cross it.  I did my first water test last night and the water hardly flowed at all.  I am using 1" pipe and got maybe 30gph.  Also the water level in the first tank ended up being much higher then the second.

How did you prime it?have any pics?

[groan]

from the site
"Getting the water up there is very simple. You turn the water bridge upside down so that the openings are facing upwards. Preferably outside, and fill the bridge, until there is no air in the tunnel or in the elbows or extensions. Do not forget the anti-chlorine. You then screw on the end caps allowing as little air as possible to be trapped in the  extension pipes and tunnel. When both caps are secure, you can go inside and at the very last minute, flip the bridge around that both of the entrances are under water. Unscrew the caps that are now under water."

[Hookup]

I believe they are using 4" pipe.  I am trying to do something similar (but with bulkheads) to connect the tanks to a central filter.  I also use strainers so the fish can't cross it.  I did my first water test last night and the water hardly flowed at all.  I am using 1" pipe and got maybe 30gph.  Also the water level in the first tank ended up being much higher then the second.

The 1" pipe is likely your problem.  I've no idea on how to do the math, maybe some engineer will chime in... but in my system I use 1.5" pipes and I have a water-level difference between two tanks setup in a relatively similar setup.  I would assume that no matter the size (within reason) there will have to be a 'high tank' and a 'low tank'.  To get water flowing you have to create that differential.  Removing water from one tank makes it "lower" than the other, and starts the flow... or pumping in water makes the other one higher.

With a nice big 4" pipe I'd bet there's enough water xfer to minimize the difference...  With 1" pipe i'm guessing that the pressure bias needs to be higher to push thru the water at sufficient volume.

As said, I'm not a fluid dynamics engineer... this could be so far off it's funny, but it's what immediately goes into my head.

[Quatro]

I added some siphons over the tops of the tanks this weekend.  In addition to the 1" pipe there is now 3x 3/4" flexible tubes and 1x 1.5" rigid pipe.  It definitely allows more flow while keeping the water levels close to each other.  I can't run my pump at maximum yet but it is about the rate I want.

I think the only variable changing is the opening size of the pipes.  <<insert math stuff here>>  The current setup has about 3.9 square inches of surface area for flow to occur at.  A 4" pipe would have about 12.5 square inches.  So the 4" pipe should be able to handle more then 3x what I can now.

My initial plan was to replace the 1" pipe with a 3" pipe (with bulkheads/under water line).  Now I am tempted to get a 6" clear PVC pipe and do the water bridge with fish swimming across.  I wouldn't want the larger fish to setup territories at the openings though.

[Hookup]

got pics?   

[Quatro]

Everyone always wants pics.   

Here is my setup as it stands now.  Two 75gals on top and seven 20gals on the bottom.  I still have some work to do on the bottom shelf.

I just did a test with a bucket and I am at about 250gal/hour with a 1/2" difference between the two water levels.

For the bottom level, each tank has a valve and a 3/4" overflow.  They will be fry tanks so I want a low flow.

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[Quatro]

Contains Moose, as for priming it, the 1" pipe I have you can see in the picture (black circles on the back glass) are underwater so it doesn't need priming.  The new ones on top of the tank I just put a airline tube into them and stucked out the air.

[Contains Moose]

     You can buy inexpensive clear fittings at a central vacuum store, might make your life easier, you can also draw any missed air out by inserting tubing to the visible bubble and sucking them out, alternatively a John Guest fitting at a high point in the bridge will make it even easier.

[Quatro]

have the water bridge setup now.  first water test will be tomorrow night.  I went with 6 inch pipe.  a little big but oh well.



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[dan2x38]

Can't wait to see more on this build and hear how the tests turned out. Nice clean work!

[Quatro]

Apparently me plus stupidity equals flood.   Hmmmm.

got it working, but the water level was pretty high.  I'll have to lower my overflow.  I have a hole drilled into the overflow pipe to prevent siphons and was curious what would happen if I plugged it.  So stupidly I put a piece of tape over it.  That definitely increased the flow.  everything looked like it was working well; lots of water being pumped into the tank, lots of water overflowing into the sump, same water level between the 2 tanks.  Then a noticed that the water level was going down.  I stop to think, that's weird and where is all the water going?  I turn around just in time to see the sump overflow.  Ignoring the stupidity of putting the tape on, I made 3 mistakes.  First I panicked and stared at it for a few seconds.  Second, I unplugged the pump that was returning water to the emptying tank.  Then I finally took the tape off to break the siphon.

All in all maybe 5 gallons ended up on the carpet.  I grabbed all my towels and started mopping it up.  I now have a dehumidifier running in the room and the towels are in the dryer.  My concern with living in a townhouse, if I have a bigger flood, will the water seep through to my neighbors unit?

[JetJumper]

Ignoring the stupidity of putting the tape on, I made 3 mistakes.  First I panicked and stared at it for a few seconds.  Second, I unplugged the pump that was returning water to the emptying tank.  Then I finally took the tape off to break the siphon.

Post that to here!
Even though its not Salt

http://ovas.ca/index.php?topic=44835.0

Atleast it was only 5Gallons and not more!  Atleast you know the water bridge works

[Quatro]

Post that to here!

I don't consider myself a newbie, just an idiot. 

[Quatro]

OK.     The system is up.  It works.    

Pump is on maximum and the water level between the 2 main tanks look identical.  Haven't seen any fish go across the bridge yet.   

Concerning my recent flooding problem.  I only had a 10gal sump which could not handle the system volume.  I moved some fish around and now have a 55gal sump.  There are a few noise issues but I have a plan. 

Thanks for the help.

[Quatro]

Wow.  Step away for a minute and stuff happens.  My 5 Afra's have ventured across the bridge.