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[JOURNAL] Mafkees' 100x40x32cm river stream biotope


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Posted (edited)

Hello guys,

I've been 'a fan of the show' for many years but somehow I hadn't heard of these forums until just now. I decided this was a nice time to join since I started a new setup a few weeks ago. I already uphold a diary on a Dutch aquarium forums but the crowd there is rather limited. 

I am hoping to interest and possibly even inspire some people with my latest build, a custom built aquarium with the following dimensions: 100cm length, 40cm width and 32cm visible water column depth.

image.png.c893a58dfa42286da222596db32f75a1.png

This system was designed with one goal in mind: to replicate a laminar flow river stream environment as closely as possible. Strictly speaking it is not a biotope because the plants and livestock have not been selected to match any biotope, but the aquarium style and build I think justify the 'biotope' label.

In short: the water flows from right to left, sweeping over the wood and across the rocks before being drawn into the left hand grid and circulated back through the right hand grid. 

In order to achieve this, a plain tank was built with 100cm length, 40cm width and 40cm depth dimensions. A false bottom measuring 78cm in length was then installed, elevating the scape-able area by approx. 8cm and thus leaving room beneath. This room is utilized to circulate water in order to achieve the desired laminar flow, and is closed off (to keep fish out) by custom designed and 3D-printed grids in each corner. The pump responsible for the water movement is an Aqua Medic Smart Flow 7.1, capping out at 10.500 liters per hour (roughly 75 times tank water volume an hour) but currently running at 35% power. 

Further tech used involves an Oase Biomaster 600 (thermo) which has considerable power but serves for biological filtration purposes only, a Chihiros WRGB II light in 90cm length, a basic pressurized CO2 kit and a surface skimmer. 

image.png.c22f81f6f1433bfc5f6de23fc8d64bc7.png

I'm looking forward to hear your thoughts on this build.

Kind regards from across the Big Pond,
Mafkees

Edited by Mafkees
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Nice looking build.  For those of us who aren't super familiar with the metric system, I did some number crunching, and the visible portion of the tank is ~34 gallons, with the total being a little over 42 gallons.  

What do you plan on keeping in it as far as livestock goes?  I've done my attempt at a stream flow tank with a stream flow manifold in a 20 gallon wide (~76x30x30 cm), and while I think my livestock is very happy, I've still not quite gotten the side to side flow I want.  I have hillstream loaches, white cloud mountain minnows, and red cherry shrimp (and a lonely otocinclus), and my setup gives me some super high flow areas, along with some lower flow areas that they can chill out in, so everyone can have what they want if they move around the tank.  

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Posted (edited)

Thanks, you guys, for the kind words.

4 hours ago, RockMongler said:

What do you plan on keeping in it as far as livestock goes? 

Current stocking is 12 white cloud minnows and 18 corydoras aeneus. The cories seem to be doing well but local suppliers seem to have extremely weak strains of white clouds around these parts, because every time I try to add to my current stocking, I get major losses. Therefore I think I'll leave it at this, for now. Perhaps some otos in the future, once the system is more mature. 

4 hours ago, RockMongler said:

I've done my attempt at a stream flow tank with a stream flow manifold in a 20 gallon wide (~76x30x30 cm), and while I think my livestock is very happy, I've still not quite gotten the side to side flow I want.  I have hillstream loaches, white cloud mountain minnows, and red cherry shrimp (and a lonely otocinclus), and my setup gives me some super high flow areas, along with some lower flow areas that they can chill out in, so everyone can have what they want if they move around the tank. 

Full side to side flow is not my holy grail. In fact, I am interfering with it by using my surface skimmer in the way I am, but I consider this a worthwhile trade-off. My pump currently runs at 35% power so if I'd step that up, it would overrule the surface skimmer flow with ease, but the fish currently wouldn't be able to handle it. I am raising the flow by 1% every day and I plan to cap it out on 60%. Fun fact: handling the flow is no problem for the fish currently, it is the intake grid they struggle with. Cories tend to rest on surfaces and when they rest on the inflow grid, it stresses them out when the current is too strong. 

I currently do have dead spots but I think those are both realistic and desirable, like you described. Fish should be able to relax. My corydoras (at least the bigger ones) spend most of their time scouring the outflow grid, which is the most high flow area in the tank, playing in the flow. It's a lovely sight. I strongly believe laminar flow to be beneficial to all fish that can handle the flow. It makes for a predictable water flow and avoids 'jet' effects. 

Would you mind sharing some pics of your setup, or could you point me to your thread? 

Edited by Mafkees
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45 minutes ago, Mafkees said:

Thanks, you guys, for the kind words.

Current stocking is 12 white cloud minnows and 18 corydoras aeneus. The cories seem to be doing well but local suppliers seem to have extremely weak strains of white clouds around these parts, because every time I try to add to my current stocking, I get major losses. Therefore I think I'll leave it at this, for now. Perhaps some otos in the future, once the system is more mature. 

Full side to side flow is not my holy grail. In fact, I am interfering with it by using my surface skimmer in the way I am, but I consider this a worthwhile trade-off. My pump currently runs at 35% power so if I'd step that up, it would overrule the surface skimmer flow with ease, but the fish currently wouldn't be able to handle it. I am raising the flow by 1% every day and I plan to cap it out on 60%. Fun fact: handling the flow is no problem for the fish currently, it is the intake grid they struggle with. Cories tend to rest on surfaces and when they rest on the inflow grid, it stresses them out when the current is too strong. 

I currently do have dead spots but I think those are both realistic and desirable, like you described. Fish should be able to relax. My corydoras (at least the bigger ones) spend most of their time scouring the outflow grid, which is the most high flow area in the tank, playing in the flow. It's a lovely sight. I strongly believe laminar flow to be beneficial to all fish that can handle the flow. It makes for a predictable water flow and avoids 'jet' effects. 

Would you mind sharing some pics of your setup, or could you point me to your thread? 

 

Just updated today, too.

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Posted (edited)
11 hours ago, RockMongler said:

Just updated today, too.

Thanks, that was a fun read. Allow me to dive deep and perhaps explain some of your struggles. What I will write below is in no way intended to criticize your setup. Some thoughts:

Your setup
You mentioned the concentrated output from the power head has a more obvious effect on the tank than the diffuse intake on the sponges. This is explainable and perhaps best compared to a canister filter. You see, using the power head-and-pipes-concept as a manifold is similar to what happens when installing a canister filter with intake and outflow on either ends of the tank. You are creating movement in the watercolumn, opposed to moving the watercolumn. After all, you extract water from the watercolumn, put it through the pipes (alternatively, the canister filter) and then insert it back into the watercolumn through your output nozzle.

Here's the key to my point: this output nozzle has a limited surface area and physics state that moving a high volume of water through a limited surface area equals high speed flow. Let us call this high speed flow 'jet flow': a narrow and fast flow of water.

We learnt that your output nozzle is inserting a jet flow into your watercolumn, which means the areas most affected by the jet flow are those directly adjacent to the jet. As stated above: you are creating movement in the watercolumn, opposed to moving the watercolumn. Those neighboring areas will become quite turbulent due to disruption of that part of the watercolumn, whereas areas farther from the jet remain relatively unaffected.

Illustrating my theory: the area behind the output should be relatively low flow.
Further illustrating my theory: after shutting off the power head, your watercolumn should be idle within a few seconds. 

Comparison to my setup
Now, comparing my tank to yours to further illustrate my theory. There are two prime distinctions between them:
1. The surface area of the outflow. Your outflow is circular and perhaps one inch in diameter, whereas mine is rectangular (equal in shape to the watercolumn) and with a surface area equal to the surface area of the watercolumn directly adjacent to it. The same applies to the intake because that is equal in size to the outflow.
This means that any water from the outflow affects the entire watercolumn, because it is the watercolumn moving through the manifold. In other words: I am moving the watercolumn, opposed to creating movement in the watercolumn;
2. My output affects the watercolumn from below whereas yours affects the watercolumn from the side. Your output is pointed toward your intake, not promoting any water other than what's directly in between them to move.

My setup eliminates turbulence because there is no movement in the watercolumn and guarantees an equal distribution of flow through the tank (if you leave hardscape out of the equation, because hardscape of course obstructs the flow and alters the mechanics of water movement). I have in fact tested my powerhead on 100% capacity (75x tank volume circulation per hour) and the minnows handled it no problem. That is because the flow is diffused over the entire watercolumn. 

Illustrating my theory: the water speed is roughly equal in any given part of the tank.
Further illustrating my theory: after shutting off the power head, my watercolumn takes a few minutes to settle (because it was moving, opposed to creating movement in it). 

Conclusion (& solution)?
Do the fish mind? Your fish are happy, evidently. Breeding and all. All of the above was merely an attempt to give proof of concept. From your journal however, I could tell you are looking for solutions to your problems with different flow levels throughout your tank. Allow me to propose a solution to your problem with the flow, of course this is only theory from my part but it might be worth a shot. 
1. Lower your output spraybar to roughly ground level, pointing it either straight up or slightly toward the right hand glass (away from the intake side);
2. Only place intake holes facing the left hand side glass (away from the output side), so water is forced to the other side of the tank, affecting a maximum proportion of the total watercolumn. 

Please consider the graphs below. The top one is your current setup (question marks indicating low flow spots) and the bottom one is my proposed solution. 
image.png.d19769e74f1bbacd4a26ab085704901a.png

Edited by Mafkees
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Yeah, I've been playing around with it a little bit, making a different spreader bar, etc.

With the current spreader bar I have on the power head, alongside making sure the power head intake isn't clogged with snails/algae, I am getting something that resembles what I want.  Your setup is much more ideal because everything can be so much more diffuse on both the intake and output side, but after kind of messing with it for 6 months or so, I've settled down and am happy enough with the flow (especially considering the time and money investment not being terribly high on the streamflow manifold). 

What really ends up being tricky for any setup like what we are doing is the aspect ratio of the tank.  It's hard for the water to get that smooth side to side flow in such a short length.  The more I've sat down and watched during feeding time how food particles get moved around the tank, though, the more I realize the setup I have with the rather turbulent water on the right side (with both a hang on back filter and the powerhead), does get a fairly nice, smooth laminar flow through the hygrophila towards the large sponge intakes on the left.  The small pieces food I drop in on the very turbulent right side will get pulled into the water column by all the mixing, then get smoothly slid across towards the more gentle flow by the sponge intakes.  I think given how relatively small my tank is for a hillstream setup, I couldn't get much better (especially not without tearing up everything and really disturbing all the livestock).  At some point, I might build yet another spreader bar (I would need to get more joints/caps, because I still have available straight tubing, but there has been a shortage recently because the great freeze Texas had a few months back ruined a lot of plumbing) that would spray the output directly back towards the glass on the right side as you propose.  Also, within the intakes on the left side, I have drilled many holes through the PVC pipe that is covered by the intake sponges, so water is being taken into the stream flow manifold from many levels within the tank.  TurbulentToLaminar.jpg.21a1c0fcc4b5d491efe2ad42f193fa8d.jpg

Attached is what I think I kind of have going on within my tank, only really highlighting the plumbing within the tank.  Because I have the current spreader bar spreading water flow perpendicular to the length of the tank, I get a super turbulent area, but then I get relatively clean laminar flow towards the sponge intakes past the highly turbulent area.  I think for my livestock it works out well, because the WCMM will spend sometimes playing around in the turbulent area, but spend a lot of time shoaling in the more smooth, slow flow in the rest of the tank.  The hillstream loaches seem to really like the high flow turbulent area (especially because of the small pile of cobbles).  The invertebrates just kind of hang out everywhere in the eternal search for snacks.

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If you compare the picture below to the one in my opening post, you'll notice most of my plants have turned distinctly brown. This is diatom algae, a phase I assumed I'd skip because of my mature filter. I however didn't turn out that lucky.

I added ten otocinclus (who are accustomed to dry foods, too) to deal with the diatoms.

Also, I finally I added a background plant to increase the sense of scale. I think this succeeded nicely. 

image.png.90ed1608357a0365ca4366f0e7cff210.png

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