Along with a past experience with keeping a stream biotope tank, two recent, reasonably unrelated experiences have given me an idea for a stream tank which I've never seen the like of before. I once kept a school of a dozen Rainbow Shiners, a few Rainbow Darters, and a couple of Cambarellus schuhfeldti in a 30 gal tank which had a 2600 gph SEIO circulation pump on it. The Shiners in particular truly seemed to enjoy the insane amount of flow exhibited really intense schooling behavior. Recently a day behind the scenes at the Adventure Aquarium introduced me to diy Kreisel tanks, which are used to create circular flow for the aquaculturing of pelagic Jellyfish. I quickly realized that the system seemed amenable to modification to provide a high degree of linear flow in a system with very high amounts of total flow. This is something which the currently popular manifold systems don't do very well, for one main reason: turbulence. Simply put, flowing water from the narrow nozzles of typical powerheads across a distance and requiring it to enter small intakes to return to the pumps inherently creates large amounts of turbulence which detracts from total velocity. And to make matters worse, the act of all that moving water suddenly hitting a solid glass wall certainly doesn't help in regards to turbulence! But a recent thread here has shown a way to avoid having things rapidly moving across the tank from encountering a solid wall. I've thought about all this, and mused a bit with friends and online, and then a 40 gal long aquarium fell into my lap. It's 48" x 12" footprint seem a reasonably good dimension for a small scale model of my design before I start messing with the 96" x 18" 180 that is where ultimately intend to apply it. Essentially there will be an "L" shaped plenum installed in the tank. The vertical end will extend above the running water level of the system, and will be placed as close as possible to one end of the aquarium while still allowing space for the pumps which will provide the water movement. The horizontal element will extend to within approx. 4" of the opposite side of the tank to allow unrestricted return flow back to the pumps. This opening will be screened off with gutter guard as a precaution against fish entering the plenum, and a small vertical lip to assist in keeping the substrate in place will be added. The plenum will be supported on lengths of 1.5" pvc. Near the screened off end of the plenum I will be installing a double thickness of the sheet biofilters commonly used in ponds. Essentially it's a tangled woven mess of fairly large diameter polypropylene "thread" similar to heavy fishing line but much stiffer. It holds its shape well under high flow and collects and holds a lot of sludge. I believe it will also soften the transition of the water into the plenum by creating a more gradual deceleration of the water. Anyway it's my project for tomorrow, most of the materials are already on hand. Pics to follow.
High Flow Stream Tank
Started by
Guest_Subrosa_*
, May 18 2013 02:14 AM
5 replies to this topic
#2
mattknepley
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Posted 18 May 2013 - 06:01 AM
Interested to see the results. I'm looking forward to doing a very high-flow stream tank some day, on the same scale as your test model. Having toyed with powerheads, I quickly came to realize that the turbulence, while kind of fun, made any stream tank with the velocity I would like impractical. Unless I either ran the tank half full or accepted water blasting into the light light fixtures and all over the floor. The first I could scenario I could deal with; the second is a very limiting factor!
Matt Knepley
"No thanks, a third of a gopher would merely arouse my appetite..."
"No thanks, a third of a gopher would merely arouse my appetite..."
#3
Guest_Subrosa_*
Guest_Subrosa_*
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Posted 18 May 2013 - 02:15 PM
Here's a crappy pic with the plenum dry fit in the tank.
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#4
mattknepley
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Posted 19 May 2013 - 08:13 AM
Cool. I think I understand the return system pretty well. It's the discharge I want to make sure I understand. The proximity of the pump discharge to the vertical part of the plenum keeps the turbulence in the plenum area while the ambitious (for lack of a better word) water slides over the top of said plenum, allowing for fast current but less turbulence. Is that right? If not, how does it work? Keep in mind you're dealing with someone whose most advanced current engineering thus far consists of running hob and ug filters in the same tank! 
Matt Knepley
"No thanks, a third of a gopher would merely arouse my appetite..."
"No thanks, a third of a gopher would merely arouse my appetite..."
#5
Guest_Subrosa_*
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Posted 19 May 2013 - 01:23 PM
The discharge of the pumps will protrude through the vertical wall of the plenum, while their side situated intake ports will remain on the opposite side. With the mattenfilter to buffer the flow before it enters the plenum, I think very linear flow can be achieved in the display section. The downside is the reduction in the viewing area of the tank, but this reduction, about 12" total, is a constant, dictated by the length of the chosen pumps and the thickness of the mattenfilter. It's a big chunk of a 4' long tank, but on a 6' tank it wouldn't be so bad, and on the 8' unit I have it'll be easily hidden and still leave a nice long stretch of stream. If it works........
Edited by Subrosa, 19 May 2013 - 01:24 PM.
#6
mattknepley
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Posted 03 June 2013 - 05:21 PM
Any progress on this front recently? Would like to hear how it's going.
Matt Knepley
"No thanks, a third of a gopher would merely arouse my appetite..."
"No thanks, a third of a gopher would merely arouse my appetite..."
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