River tank manifold water flow

[oilhands]

I setup a river tank manifold similar to that which Martin has outlined for all of us. I just added some tall live plants last week and I am seeing circular/vortex water flow patterns similar to that discussed in the forums (http://forums.loaches.com/viewtopic.php?t=16061) in recent days. I have an idea on how to deal with this, but I'm not sure if it makes any sense.

Basically, I've been thinking that the river tank manifold itself needs both an intake and an exhaust manifold. Currently my setup has the three intake sponges lined up along the bottom at one end of the tank. Space is available for three exhausts (powerheads) and being cheap I only have one at the moment. Air stones are also moving the water some...I assume up the back wall of the tank given the flows of plants in the water.

Anyway, the idea is to equalize the flow of water. The intake manifold would likely have as many as 10 to 20 individual intakes. Even better would be something like an undergravel filter plate standing up on edge with the intake or intakes sealed against a drilled back box holding it in place. The exhaust pumps would be attached and fashioned in like manner. Spreading the flow evenly from top to bottom I think is the key.

I wonder how these folks (http://www.endlesspools.com/endlesspool/index.html) make their Endless pool work.

I have checked out their web site and watched their video, but I could not see a clear view of the water return (intake) mechanism they use for the water. Their exhaust manifold looks like a screened in louvered box with about 6 slats with one big pump.

[Martin Thoene]

Any River-Tank Manifold has equal intake and "exhaust". It can only intake what the powerheads "exhaust". It's ultimate flow capacity is limited by the maximum flow capacity of the powerhead(s) v's tube internal diameter.

The Endless Pool principle basically uses a large fan to shift huge quantities of water. It is something I've seriously looked at because I believe it represents the best possible way of creating an absolutely true uni-directional flow.

I know how to do it in an aquarium and it's something we've discussed here in the past. The only problem is aesthetics and complexity....plus it needs some equipment which is most unconventional for use in aquaria.

A large chunk of the total aquarium decorative space will be lost to contain the drive fan which moves the water. The design concepts for the River-Tank manifold were utilization of the maximum space available in a given tank, simplicity, ease of reproduction with locally available fittings and pipe, ability to use the manifold in smaller or larger tanks over time if required (easily changed in size after initial build), low maintenance and use of easily obtainable conventional aquarium equipment, i.e. the powerheads.

Flow reversals are an inevitability of the design due to the pressurized, concentrated nature of the output of conventional powerheads. They are by nature gentler than the powerhead push of water toward the intake sponges. They're not bad because flow reversals happen around obstacles in natural streams anyway.

Ultimately, my River-Tank manifold design works pretty well because it embraces the KISS principle which usually helps in DIY engineering.

Martin.

[Diana]

Going beyond the KISS principle I can see a UGF plate (Perhaps egg crate would allow better water flow) at each end, and a sump. The siphon (or drill the tank) is camouflaged behind one plate, perhaps the plate has some rocks glued to it, but there are still enough holes for water to flow freely. The outlet from the pump discharges into the void between the plate and the other end. Similarly, this plate is camouflaged, but still has lots of holes for water flow.
To create more intense flow I suppose the outlet could actually be a plumbed array of pipe stepping down in size to perhaps 1/2" outlets spread over the area behind the plate, but aimed in the right direction.

The flow is still limited by plumbing (pump capacity and pipe sizes) However, most of the equipment is now out of site, and the additional volume in the sump increases the size of the system in terms of water volume and diluting the waste. The additional exposure of water surface to air ought to be better for the high oxygen requirements of our fish.

[oilhands]

I'm not at all unhappy with your existing river tank manifold design. Curiosity just got the better of me when I got to thinking about what I was seeing in the tank.

I figured that available tank space would be an issue for the creation of any kind of box and that any solution might be very complex. Which is a bummer. I wonder if the vortex action is a matter of intake/exhaust placement or uniformity of flow. The Endless pool's fan pump could be replaced by powerheads or mag pumps if they could be fitted to a box like they use. I was actually more interested in the intake side, but I can't see any of the details on the Endless pool's intake.

Maybe having the intake sponges located near the bottom of the tank is creating the toilet flush type vortex. Maybe just moving them up higher in the tank would reduce this effect. Have you heard of anybody trying that? Can you think of any reason why that wouldn't be a good idea?

I guess it is possible that the exhaust flow has more to do with the direction of the vortex rather than the Coriolis effect.

And then I read this: http://en.wikipedia.org/wiki/Coriolis_e ... lis_effect

[chefkeith]

I don't get the bad vortexes in my river tank

[oilhands]

I don't get the bad vortexes in my river tank

Was it just a matter of tinkering with your powerheads until everything balanced out?

[Diana]

Would a larger array of pipes and intakes reduce the vortex? If the intake surface area was larger then the water would not be drawn so intensely into a small location. Perhaps something like a ladder with the rungs all slotted or drilled for intake, then covered with sponges. Collect all that water into a couple of legs (probably a larger pipe size) then down under the sand to as many power heads as are on the other end of the tank.

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[oilhands]

Would a larger array of pipes and intakes reduce the vortex? If the intake surface area was larger then the water would not be drawn so intensely into a small location. Perhaps something like a ladder with the rungs all slotted or drilled for intake, then covered with sponges. Collect all that water into a couple of legs (probably a larger pipe size) then down under the sand to as many power heads as are on the other end of the tank.

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I like that idea. When I think about the intake or exhaust I wonder how you would balance the pressures between the various openings so that they are nearly equal. Like you posted above, some sort of variable sized openings which are larger or smaller as you get farther or nearer to the main pipe. Then again, maybe it wouldn't matter that much as long as the flow wasn't concentrated in a handful of openings.

I still would like to see what the Endless Pool folks came up with for a solutions. Looking closer at their site my best guess is a giant finely grated box with multiple return ports up and down the inside of the box.

[chefkeith]

Was it just a matter of tinkering with your powerheads until everything balanced out?

No, just a different philosophy and design.
What I did is I put a large island in the middle of my tank and the water flows around the island in one direction.
Like in this diagram-

[chefkeith]

I figured that if I wanted to use a manifold type design on my river tank and wanted a flow rate of 1 ft per second I would of needed a pump and plumbing that is capable of 96,000 gallons per hour.

[Martin Thoene]

I figured that if I wanted to use a manifold type design on my river tank and wanted a flow rate of 1 ft per second I would of needed a pump and plumbing that is capable of 96,000 gallons per hour.

Herein lies the problem with conventional pumps. The Endless Pool works with what is basically a propeller encased in a housing. It shifts enormous amounts of water.

Martin.

[oilhands]

I figured that if I wanted to use a manifold type design on my river tank and wanted a flow rate of 1 ft per second I would of needed a pump and plumbing that is capable of 96,000 gallons per hour.

Herein lies the problem with conventional pumps. The Endless Pool works with what is basically a propeller encased in a housing. It shifts enormous amounts of water.

Martin.

Wow. I'm stunned. You would need 32 of these 3,000 GPH Quiet One pumps I have been looking at buying.

I guess I should be happy that the water in the tank is moving around at all. Thanks for putting this in perspective. I just had no idea of the scale of the problem we are dealing with.

Electric bill?
Purchasing costs?
Noise?

I'll just let this idea go.

[Tinman]

The endless pool uses a large propeller or impeller that move more water based on blade area, The pumps we use are 1/2" impellers so they can not match a large blade for movement.A large blade could be used with a top mounted motor and the bottom of the tank grated and reduced to about 2" high with plexi would create a venturi effect and give the rates of flow with a refugium for the fish to get a rest.
85% of the tank or more would be used for propeller and about 5-10% for the fish habitat, not very desirable for a show tank....

I guess I should be happy that the water in the tank is moving around at all. Thanks for putting this in perspective. I just had no idea of the scale of the problem we are dealing with.

Electric bill?
Purchasing costs?
Noise?

For a 20X turnover on 1000 US gallons I have a 2 horsepower pump at 4800 watts plus Turbelles at about 40 watts pluss cannisters and Fluvals for a 20,000 gallon an hour flow I use about 7500 watts plus heat at about 15,000 watts. My house has distinct hum.

To increase your flow decrease your tank size increase your pump size ,as Martin said KISS.

I have thought about a gravity fed stream but again you are limited by pump blade size. A venturi can greatly increase flow rates and would be the only economical way to attain the rates you seek or think of

[Martin Thoene]

I had worked out to keep it smaller than that Tinman...maybe 25 -33% of a 4 foot tank, but then there's less than 3 foot of useable fish and decor container.

I was thinking car cooling fan around 12" diameter encased in a circular housing and driven by a ceiling fan motor because these run near silent and will go for years rotating a 50"+ fan with relatively low electrical consumption.
A false floor for water transfer and perforated end walls on the inner box containing the fish and decor.

It's doable, but would probably look like crap. OK in a fish-room, but not aesthetically home-friendly.

I did have drawings, but dumped them when I moved recently and changed computers.

Martin.

[Tinman]

You are correct Martin, The whole top could be area and the water through the venturi into the pump could be the river with the propeller at one end. This would leave much of the tank calmer as the refugium, Air blade would not be the best but would work, I was thinking boat prop for the variable pitch to increase flow proportionally but what logistics and you said it perfectly

It's doable, but would probably look like crap. OK in a fish-room, but not aesthetically home-friendly.

The river could be across the front as the high flow the fish would not care vertical from horizontal so the front glass would be the 'bottom" of the river leaving 100% viewing area. Two 6101 or 6301 Turbelles would be comprable for the effort me thinks....and so might the fish.