Posted: Wed Jan 07, 2009 11:34 pm
I did a little work with my 20 gallon long tank.
This tank is 30" (75cm) long, and 12" x 12" (30 cm x 30 cm)
I have an Eheim Ecco 2234 with the intake at the left lower back corner and outlet at the right upper back corner, aimed slightly toward the front of the tank. It hits the front glass more than halfway toward the left end.
I have an Aquaclear power head also on the right end of the tank, pretty close to the middle of the right end. Intake is at the left end of the tank, just about the middle of that end. It also is aimed slightly toward the front, and hits the front of the tank just about the middle of the glass. The flow from these two sources starts out parallel.
The Hagen site (they make Aquaclear) says 270 gph (But take that with a grain of salt) 145 gph for the Eheim.
With somewhere between 300-400 gph (1200-1600 lph) on a 20 gallon tank there ought to be something like a river going on in there. I have Darters in there, a lot like Schisturas.
Decor is relatively open, rounded rocks on the floor of the tank, a couple of pieces of small driftwood, some plants that stay low.
There is some duckweed at the surface and I can follow that around to figure out what the water is doing at the surface. There are not really any plants in the middle of the tank to watch. There are a few plants at the left (intake) end. When I pull off the sponges the plants try to enter the intakes. Other than that I cannot tell what is going on lower in the water. These plants do not move much. They are sort of stuck at that end, though, they do not grow out into the rest of the tank. Certainly I can stick my hand in and feel the power head, but anything finer than that is probably affected too much by my hand being in the water.
The surface is swirling around, clockwise. This seems to be due to the Ehiem. The outlet is aimed this way, and the movement continues, even when I unplug the power head. There is no vortex, though. Just swirling Duckweed. (It must get dizzy!) There is a small anticlockwise swirl in the front right corner.
Spas and Swim-spas:
My company has installed a few Nespa swim-spas. They are not exactly the same as an Endless Pool, but the idea is the same. Their basic design is a 2-part spa and pool, with a wall in between (the wall is optional, but gives you a spa on one side and a small pool on the other.) If you want the pool section to have a strong flow so you can swim laps (Endless pool style) they will set it up this way. The equipment is similar to a full sized pool, so all the normal inlets and outlets found in a large pool are concentrated in the small swimming section of Nespa's Swim Spa. Pumps up to 3 hp are detailed at the Nespa website, with performance up to 160 gallons per minute (yes, per minute: this is 9600 gph) This swimming section can be made to order, but several of out clients have ordered it roughly twice the size of a normal spa so there is room to swim in it with a good current. Without the current it is not much more room than an oversized spa, and an adult would not likely get more than about 2 strokes before hitting the end.
This is all remote equipment, similar to a swimming pool.
Relating this to an aquarium: You could probably design a similar thing, plumbing and remote equipment, but the inlet and outlet design and layout will be critical to give you a good river flow. There are likely to be counter currents in any set up, though, even if you figured out how to make the entire area of the end be the inlet and outlet.
As noted several posts ago: even a fast moving mountain stream has quiet pockets, and sections where the current is flowing 'backward'.
To give the fish a choice of water movements is very important. As much as they need the high flow, high oxygen set up, they also need quiet places. Many of the Hillstream fish do not spend so much time directly in the maximum flow of the water, but wait in these quiet pockets for an insect to land on the water or swim by, and dart out to get it. Darters, for example do just this. Mine are rarely right in the flow, but are usually just out of it, perched on a rock or the substrate. There are of course a good selection of fish that do stay right in the stream, too.
Another problem with adding more and more pumps: Most of these are water cooled, and the water that cools them is the aquarium water. By the time you get that much water flow in such a small volume of water you will probably be overheating the water, especially in the summer.
This tank is 30" (75cm) long, and 12" x 12" (30 cm x 30 cm)
I have an Eheim Ecco 2234 with the intake at the left lower back corner and outlet at the right upper back corner, aimed slightly toward the front of the tank. It hits the front glass more than halfway toward the left end.
I have an Aquaclear power head also on the right end of the tank, pretty close to the middle of the right end. Intake is at the left end of the tank, just about the middle of that end. It also is aimed slightly toward the front, and hits the front of the tank just about the middle of the glass. The flow from these two sources starts out parallel.
The Hagen site (they make Aquaclear) says 270 gph (But take that with a grain of salt) 145 gph for the Eheim.
With somewhere between 300-400 gph (1200-1600 lph) on a 20 gallon tank there ought to be something like a river going on in there. I have Darters in there, a lot like Schisturas.
Decor is relatively open, rounded rocks on the floor of the tank, a couple of pieces of small driftwood, some plants that stay low.
There is some duckweed at the surface and I can follow that around to figure out what the water is doing at the surface. There are not really any plants in the middle of the tank to watch. There are a few plants at the left (intake) end. When I pull off the sponges the plants try to enter the intakes. Other than that I cannot tell what is going on lower in the water. These plants do not move much. They are sort of stuck at that end, though, they do not grow out into the rest of the tank. Certainly I can stick my hand in and feel the power head, but anything finer than that is probably affected too much by my hand being in the water.
The surface is swirling around, clockwise. This seems to be due to the Ehiem. The outlet is aimed this way, and the movement continues, even when I unplug the power head. There is no vortex, though. Just swirling Duckweed. (It must get dizzy!) There is a small anticlockwise swirl in the front right corner.
Spas and Swim-spas:
My company has installed a few Nespa swim-spas. They are not exactly the same as an Endless Pool, but the idea is the same. Their basic design is a 2-part spa and pool, with a wall in between (the wall is optional, but gives you a spa on one side and a small pool on the other.) If you want the pool section to have a strong flow so you can swim laps (Endless pool style) they will set it up this way. The equipment is similar to a full sized pool, so all the normal inlets and outlets found in a large pool are concentrated in the small swimming section of Nespa's Swim Spa. Pumps up to 3 hp are detailed at the Nespa website, with performance up to 160 gallons per minute (yes, per minute: this is 9600 gph) This swimming section can be made to order, but several of out clients have ordered it roughly twice the size of a normal spa so there is room to swim in it with a good current. Without the current it is not much more room than an oversized spa, and an adult would not likely get more than about 2 strokes before hitting the end.
This is all remote equipment, similar to a swimming pool.
Relating this to an aquarium: You could probably design a similar thing, plumbing and remote equipment, but the inlet and outlet design and layout will be critical to give you a good river flow. There are likely to be counter currents in any set up, though, even if you figured out how to make the entire area of the end be the inlet and outlet.
As noted several posts ago: even a fast moving mountain stream has quiet pockets, and sections where the current is flowing 'backward'.
To give the fish a choice of water movements is very important. As much as they need the high flow, high oxygen set up, they also need quiet places. Many of the Hillstream fish do not spend so much time directly in the maximum flow of the water, but wait in these quiet pockets for an insect to land on the water or swim by, and dart out to get it. Darters, for example do just this. Mine are rarely right in the flow, but are usually just out of it, perched on a rock or the substrate. There are of course a good selection of fish that do stay right in the stream, too.
Another problem with adding more and more pumps: Most of these are water cooled, and the water that cools them is the aquarium water. By the time you get that much water flow in such a small volume of water you will probably be overheating the water, especially in the summer.
