epic stream tank

[fredmanby]

Apologies if this is the wrong forum -- first proper post!

I've read on loaches.com about the famous river-tank manifold, which is a great idea, but comes nowhere close to delivering the water movement of a real stream environment.

Suppose you want a gentle flow rather than a raging torrent. Say 1 m/s (ie 2-and-a-bit miles per hour).

At this speed, 1 m^3 = 1000 ltr passes through an area of 1 m^2 every second. Assume you want a cross-section of 1 square foot, which is about 0.1 m^2. Then the flow of water has 'only' got to be about 100 ltr/s. Note the 'per second'

That's 360,000 ltr/hr or about 100,000 gph.

This is probably nothing to the monster fish keeping community , but to me that seems like a lot of water movement!

Well, anyway I just wondered if anyone wanted to discuss this, and if so it would be great to share some ideas about how to create water movement on such a scale.

 

[Noto]

I wouldn't call 1 m/s gentle flow, but it is certainly less than what many fish deal with in the wild. I'll see if I can find some stream velocity data to correlate velocity with stream types.

Your point stands, though. I doubt many hobbyists are providing that kind of flow. Besides the expense of the pumps, you would need to add a chiller thanks to the heat transfer from all the pumps; even inlines bleed some heat.

 

[Tanyoberu]

I never saw that river system but thought of the exact same thing (never implemented) for the columbian sharks I was keeping. I realized that the direct flow from the powerheads would concentrate too much force in one area and concluded that I'd have to diffuse the flow by turning the powerheads around so that the output would hit the walls of the tank before flowing to the input sponges.

In the end, I just used the powerheads and sponge filters on one side but it created a circular flow. The top water moved in one direct, the bottom back towards the intakes. You could see how the fish on the bottom stayed in a constant swim pattern in opposite directions and how there were neutral spots in the middle of the tank.

Ok, I'm babbling... I have some pictures somewhere on here where you can see the flow in my 80 gallon tank.

 

[fredmanby]

I wouldn't call 1 m/s gentle flow, but it is certainly less than what many fish deal with in the wild. I'll see if I can find some stream velocity data to correlate velocity with stream types.

Well that would be great -- thanks Noto.

Your point stands, though. I doubt many hobbyists are providing that kind of flow. Besides the expense of the pumps, you would need to add a chiller thanks to the heat transfer from all the pumps; even inlines bleed some heat.

I agree. These cold-water species will not appreciate 1000 W of heating So there is a key design criterion: the pumps have to deliver minimal energy to the water. Ecotech make pumps for reef systems with the pump motor outside the glass. Somthing like this could be useful!

In the end, I just used the powerheads and sponge filters on one side but it created a circular flow. The top water moved in one direct, the bottom back towards the intakes. You could see how the fish on the bottom stayed in a constant swim pattern in opposite directions and how there were neutral spots in the middle of the tank.

Ok, I'm babbling... I have some pictures somewhere on here where you can see the flow in my 80 gallon tank.

Thanks Tanyoberu, it would be great to see the pics.

 

[jaytech33]

I have the "river tank manifold" setup in my 90 gal. 2 300gph power heads. I can say that my clowns and the plec love it. The clowns love to fight the current and the plec likes to sit on a big rock in the line of fire of one of the powerheads.

 

[fredmanby]

I have the "river tank manifold" setup in my 90 gal. 2 300gph power heads. I can say that my clowns and the plec love it. The clowns love to fight the current and the plec likes to sit on a big rock in the line of fire of one of the powerheads.

Sounds great -- do you have pics uploaded?

 

[micstarz]

In most rivers, there are pockets of non-moving water (behind boulders)...so fish can take a break from the current when necessary. Just a thought...

 

[fredmanby]

When I was thinking about this, I decided horizontal motion would be best, since pumping up hill is some work

As Noto said, heat transfer could be a problem. But here is a thought. (It;s a silly thought, but you have to start somewhere).

Make a tank from two cylinders, one small one inside a larger one, so that it looks like this from above:

Suppose the water is circulating: if there is no frictional energy loss due to the walls, decor, fish etc, the water just keeps going round forever! Of course there will be energy loss, but the pumping mechanism only has to contribute the energy that is lost; or to put it another way, if there is a pump at some point round the circle, the water goes IN to the pump with some given speed.

The only problem is how to construct such a tank!

Let me know if you think this is possible/interesting/crazy/pointless, etc...

 

[Tanyoberu]

http://www.monsterfishkeepers.com/gallery/showphoto.php/photo/19828/ppuser/8329

You can see the two powerheads pushing up top. And though you can't see the current, the columbian sharks stayed 'swimming' in the current heading back to the sponge filters. Overtime the current and the fish removed the rocks that were covering the slate that was anchoring the driftwood down.

http://www.monsterfishkeepers.com/gallery/showphoto.php/photo/19833/ppuser/8329
This is the top of the tank at the other end. You can still see the water pushing 6' across.

My point is that in an enclosed area I found that I got lots of directional movement that satiated the fish that enjoy 'swimming'. I like the river system idea, but was pleased with the movement the powerheads supplied this way as well. And these were some of the greatest biological filters!

 

[Tanyoberu]

http://www.youtube.com/watch?v=kD7AV9U5t4I&feature=channel_page
And a video so you can see the tank in action. Note how the catfish learned to stay stationary by tilting up enough to keep the tail fin planted, but the pectoral fin in the current keeping them afloat.