Fountain Pump for water bridge?

[Katy]

OK, now we are getting the 40 gal set up, have it raised a couple inches so the water levels will be even. The plan is for the 40 to be a higher-flow tank than the 54, so used river gravel for substrate (to protect the powerhead from sand). Would like the flow through the water bridge to be gentle, but moving from the high-flow tank into the bigger tank (so no dither fish are tempted into the high-flow and then encounter difficulty swimming back). We are also discussing having the UV filter between the tanks with a fountain pump powering flow (lower flow rate than any of our filters)

Anyone have suggestions for a quiet, fairly low-flow rate fountain pump for this use?

And has anyone used flexible tubing for a water bridge instead of PVC or acrylic?

Thanks for all the advice!

[Keith Wolcott]

Some things that I thought about when installing my water bridge.

1. Since many fish tend to like to swim upstream (my tank has a horizontal circular flow and the dither fish all swim around in a circle in the upstream direction) you might want your flow through the bridge in the opposite direction. On the downstream end of the bridge the fish may also smell food and follow it through. I have had dither fish go through both directions, but only one in each direction (Giant danio upstream and Brilliant rasbora downstream) so it may not matter much. I think it was most likely a complete accident since the dither fish are not very curious and do not really explore. After a day or so, I netted them and put them back since they seemed so miserable by themselves.

2. If you lose the siphon through the water bridge (plants could block it or it could develop a leak), it is best if your pump does not continue pumping water into the other tank to overflow it. One way to do this is to have the pump input mounted very high in the water so that it can only pump a small amount of water into the other tank. Another way is the solution that I have used which is to use the venturi of a powerhead to pull water from one tank to the other. Mine just moves it at 15 gal/hr and does not have enough power to overflow the tank if the bridge fails.

I believe Wolfram of this list has used flexible tubing for his bridges. He has pictures on several posts.

Good luck and please post pictures when you get it installed.

[Katy]

Yes, the concern for what would happen if flow was lost through the bridge is why we want to keep flow pretty minimum.

There will be photos.

[Diana]

I used a fountain pump of about 100 gph for the water bridge. The bridge itself was 2" PVC, and never got blocked by plants or anything else. The bridge extended into the tanks about half the depth of the tanks. The fountain pump pumped water through a vinyl tube into the other tank, and the fountain pump's intake needed to be kept clean. Mostly not much of a problem, with that slow a flow rate.

I did not have any problem with either tank overflowing. I could even do a water change in one tank, and run the refill water into the other tank. Both tanks would fill equally.

[chefkeith]

I've only had new water-bridges fail. But once they were tested and the leaks were found and fixed, they never leaked again. (knock on wood)

One failsafe I use is much like the 1st one that Keith mentioned. The intake for the circulation pump is a few inches from the surface. For circulation, I use a 300 gph Eheim Pro II canister filter connected to a 36 watt turbotwist UV.

A water-bridge is mearly a large siphon. So don't make them go down to the bottom of the tank, unless you have siphon breaks in it. Otherwise, if one tank empties, they'll both empty. My other failsafe is that my water bridge entrances only go down about 4" from the surface.

This thread is sparking my interest to upgrade my water-bridges again. Yes, another winter project might be on its way.

[wasserscheu]

...

And has anyone used flexible tubing for a water bridge instead of PVC or acrylic?

Thanks for all the advice!

just a quick reply... pics below show pvc-flex-hose combined with sewer(wastewater) pipes...











garra rufa are the most busy commuting between shown tanks ... loaches, prefer the other side (not shown)