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Well, looking in the mirror, I have to say I do like my pouty face. But tonight I stumbled on something that everyone involved in the freshwater hobby must hear.

Especially if you are in the planted tank side of the freshwater hobby. And especially if you think Amano is a genius or just a clever marketer of cool looking glass filter pipes.

Here: A discussion on a reef forum about water flow and how it affects a saltwater aquarium. Started in 2006:

http://www.zeovit.com/forums/showthread.php?t=8740&page=2

On page 2 there are two things that hit close to home:

1. "...turbulence disrupts the boundary layer at the surface of a coral (facilitating higher nutrient uptake rates)..."

2. "...turbulence has the ability to transiently concentrate stuff in the water column..."

That tells us, planted aquarium folk, that we should know more about laminar/turbulent flow and how they affect our planted aquariums. It also tells us that we are way behind in our understanding of how the water should move in our planted tanks. Nice, eh?

From what I know abot the way ADA sets up their water flow they do try to avoid too much turbulence. I cannot say they are trying to achieve perfect laminar flow. But for sure the design of the Lily pipe now seems much more elaborate than I ever thought. I maybe way off in my thinking.

But we cannot deny that if the type of water flow has the ability to "facilitate nutrient intake" and "concentrate stuff in the water column" in a reef tank then we got to know how it all works in a planted tank.

It certainly feels like we are on to something new here.

--Nikolay
 

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And please look at Jake Adam's articles titled "Water flow is more important for corals than light." parts I and II.

Freshwater plants are not corals, but once again - what do we know about flow, light, nutrition, and particles in our tanks.

--Nikolay
 

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"From what I know abot the way ADA sets up their water flow they do try to avoid too much turbulence. I cannot say they are trying to achieve perfect laminar flow. But for sure the design of the Lily pipe now seems much more elaborate than I ever thought. I maybe way off in my thinking."

To my amateur points in my last post in the "other" thread.... Maybe what they know is that stable, laminar flow in an aquarium is impossible and therefore have designed an outlet that uses drag and vortex streets to its advantage, pushing them with acquired volume "down the street".

This seems like an optimal pattern.

How could it be made a little wider?
Keep all the vortices moving towards the intake and avoiding backflow?
What role does high-pressure at the outflow side and low-pressure at the intake side play in this movement? Assuming there is a pressure variance of course. Just assuming there is.

Love this topic, wish I know more.
 

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Did you see the description of Gyres (aquariums with very prominent unidirectional water flow) in one of Jake Adam's articles? Basically you put a piece sheet plastic in the middle of the tank. Either horizontally (like a shelf) or vertically (like a wall). Then you pump water only on one side of the shelf or wall. That creates a very pronounced flow going one way.

http://www.advancedaquarist.com/2007/1/aafeature

A horizontal gyre certainly makes me think of the way the water flows with a typical ADA Lily pipe setup.





All that information is about reef tanks and corals. As I understand from the article with a Gyre setup you can actually create a lot of water movement with very little power (with a weak pump). The water gains momentum as it seems, similar to rocking a swing I guess. Maybe that's why ADA suggests a filter that moves only 2.5x the 180 gallon tank volume per hour - the dimensions of the tank are somehow optimal for the water to gain momentum with even a smaller pump. ADA suggest faster turnover rate in their smaller tanks.

In any case - this laminar/turbulent flow discussion is in place for reef tanks. Plants have got to differ in some way and definitely there is something to learn here.

--Nikolay
 

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Someting else that has been "gyrating" in my head the last 2 days;

If you have to sweep the floor and there is a lot of very fine dust you are really better off moving the broom slower and using smoother sweeping motion. Fast movements make the dust airborne and are counterproductive.

Seems to me that the fine particles in an aquarium would be collected more efficiently if you don't swirl them around, making them fly all over the place. Also when the particles float around they grind or fall apart and turn into even smaller particles.

Since I too agree that complete laminar flow is impossible in an aquarum because of obstructions and maybe the square shape I start to think that the goal is to have both laminar and unidirectional flow. Laminar so the particles do not get banged around and grind themselves into smaller pieces. And unidirectional so the particles are constantly moved toward the filter intake - both pushed or pulled toward it. Like this:

Phil pointed out to me that the ADA intake is not only situated a little below the middle of the tank, but not close to the substrate but also it has a wide "intake" area. According to him that aids the water in maintaining it's flow as close to laminar as possible. Basically the Outtake shoots in an almost almost laminar fanning pattern close to the surface of the water, and the intake "pulls" in a wide pattern - the result is forming a "U" shaped flow that engages particles from the bottom and lifts them.

--Nikolay
 

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There are 2 things about the flow that are pretty apparent if you have seen how the Lily pipe works in real life:

1. The flow pattern of the water coming out of the Lily pipe is like a fan. A fan spead under the surface of the water. Flat side up.

2. The water flow along the bottom is actually going up as it gets close to the intake. Now the fan is turned sideways - with the flat part toward the front glass. Because the water flow is going under an angle toward the intake, particles are lifted from the bottom.



That explanation certainly sounds like overthinking. But it may explain why ADA places the pipes close to the front of the tank - because there is at least some degree of "water flow twisting" that could be involving water+ particles from the back of the tank.

If that is really how it all works I'd say it's pretty ingenious - and implemented in such an elegant way.

--Nikolay
 

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Tonight I have single handedly discovered one of Amano's secrets. Yes, no exageration. It's called "a gyre". Read on:

I just re-read Jake's article and here's what I think needs to be noted:

"..In order to maximize the output of water flow equipment, aquarists should design water movement systems so that all the components work together to minimize resistance and move the entire water mass of the aquarium. The best way to combine the energy of moving water to produce maximum water motion for an aquarium is to encourage the formation of a circular course of water movement called a gyre. Like the wheel, a gyre takes advantage of feedback mechanisms which preserve momentum by minimizing resistance. An aquarium gyre somewhat resembles a conveyor belt of water movement and it is characterized by mostly laminar, unidirectional flow..."

The placement of the ADA Lily pipe and intake certainly are following that advice!

--> The pipes are in the front of the tank, where the flow is not restricted (minimal resistance + preservation of momentum).

--> The pipes form a "circular course... called a gyre."

--> The pipes "work together to... move the entire water mass of the aquarium..."

And note this: "...An aquarium gyre ...is characterized by mostly laminar, unidirectional flow..."

Phil and I invented the wheel a week or so ago! We figured out these very things. Well known already.

I feel smarter than ever before! But I do believe that there is a benefit from all that comotion - eventually we will know more about how to make planted tanks more predictable. Hopefully.

Certainly makes me eager to make my own "gyre". I bet the explanation for all this is somewhere in numerous Japanese publications. It is beyond me why we here in the US, as a community, have never had access to these things. Or could it be that we never had interest?

Well, anyway, now we know a little more.

(A combination of EI and a gyre has got to be an explosive concoction worth mixing! I have a strong suspicion that Tom Barr knew that years ago!)

--Nikolay
 

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I haven't seen a lily pipe in action in person. I do recall discussion that one of the benefits of the whirlpool that a lily creates is an immediate downward flow and that the intake was higher than typical to encourage a u-shaped movement of water in the tank...down from lily, along bottom then up to intake.

I just gave NY 8-year old a tank of her own -new fluval Studio 600. It comes plumbed from the bottom of the tank, with both intake and outflow adjacent and rear/left of the tank. The inlet is approx 1/3 down from water kine. The outlet a little higher, is a pair of jets at 90 degree angles that I have aimed to the right. The flow in that tank is much like the gyre you have depicted above. You can see it...sinking pellets follow that path. Sophisticated test eh?

It's a 24 x 17 x 18 tank, so outflow hits walls quickly. Can't imagine that arrangement would perform the same way in a larger tank. Seems intake undercurrent would eventually overcome outflow momentum and create an area of stalled flow on the opposite side of the tank.

Given that our tanks have stuff in them I can't see how that on-it's-side U shape can be achieved in a large tank.

I tend to think of flow as a function of outflow force and shape. But I wonder what role pressure variance may play in the overall movement through a tank. Does the lily just establish a wide vortex street with a little downward force as fast as possible, depending on negative pressure to then pull through the tank?
 

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This link:

http://www.ukaps.org/forum/viewtopic.php?f=21&t=11056

Contains a discussion that has a lot to do with what we are discussing here. Funny enough that thread was started on my birthday.

I don't see these guys talking about laminar/turbulent flow. Just flow rate and also relationships with other factors.

Because it's impossible to say that higher flow is always, every single time, better there are a lot of opinions. As I type this I have a 55 gallon tank that grows all sorts of plants. 54 watts of light, and cicrulation of about 30 gph. That tank never has any issues - CO2 or no-CO2, water changes or not. I have to remove handfulls of plants from it every 45 days or so. I never fertilize.

But once again - that's a case of "this works for me and I don't know why". What I'd like us to find is what works every time and we have more answers to issues.

--Nikolay
 

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yep I always wondered why I would see journals of people drilling the side of there stand for the canister tubes and now I know why. if the canister hoses are coming from the back would the return just spray water to the front of the tank? going on the sides the spray bar can shoot to the other side of the tank, then on the other side a hydor korlia power head can circle and create flow back to the intake... to where the intake can pick up debree
 

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Because the ideas kept coming Phil decided to make a separate thread with a more civilized title -this one. I still update the other thread. Both of them are in the DFWAPC sub-forum and that's an order good enough for me.

If one is interested in the topic of flow impoving their planted tank they will put the "effort" and find where the information is.

--Nikolay
 

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your welcome... speaking of hydor k power heads.. I saw nanos 240's might be the nano 425's on clearance at pet supplies for 23.97 and the k ones where 29.97 on clearance... coral-life 24 t5 normal out put light fixtures are 37.97 on clearance and the 48 inch t5 normal out put light fixtures are 49.97
 

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I have been following this thread, and playing around with my own lily pipe. What really interested me was the discussion of the gyre, and how Amano typically puts his lily pipes toward the front of the tank.

I have never noticed it until you mentioned it, but you are right. He does tend to put his outflow toward the front of the tank.

I had my outflow dead-center on the side of the tank and so I had good laminar flow, but when I moved my pipe to the back of the tank I noticed how the water would still flow in the same manner as it was before (flowing from top, hitting the other side of the tank, flowing down, then flowing back to the other side, in a circular manner) and I knew that this was the way the water moved in the tank by watching the way the bubbles from my diffuser (placed on opposite side of tank) would move.

Now, the water ALSO flows strongly along the back wall of the tank, circling around and then moving traveling along the front wall and back to the intake. Like a whirlpool. In a whirlpool in nature you would expect a dead zone in the center, but I believe the design of the lily pipe (when placed along the front or back glass, creating this whirlpool) also "folds" the water creating laminar flow that continuously drags water through the center of the tank and preventing the center from being a dead zone, despite the whirlpool effect that seems to happen (IME) when the outflow pipe is placed towards the front/back glass.

I tried to draw a quick sketch in Paint to show what I am talking about. Please look at this picture and notice that this picture can represent a view of the water flow in the aquarium when looking from ABOVE, or when looking from the FRONT. The flow seems to take this pattern in both directions. It is hard for me to articulate the words to describe what I am seeing in my aquarium based on the movement/distribution of the co2 bubbles, so hopefully you guys understand. In a nutshell, I think that by placing the outflow on the front or back of the tank, a U pattern is created but this is a double U (water moving on top, down, along the bottom then up to the intake, as well as along the back, along the side, along the front, and then up back into the intake.) All the bases seem to be covered this way.

 

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That was very intresting! I knew that once the flow is not turbulent there will be things that are not intuitive. I thought along the lines of the flow "pulling" particles from everywhere. But I never thought that the "U shape" of the flow would be the same vertically and horizontally. And on top of that - wherever you move the Lily pipe setup.

At this point I don't know if we are noticing things that Amano himself has not noticed. As I just described in the other thread after talking to Luis today it seemed to me that the original design and placement of the Lily Pipe and intake were as they are because of the CO2.

But we can't deny the venturi action, the aeration function, the surface scum sucking ability, and the flow that seems to really, really make sense in every dimension. On top of that the glassware looks way better than any plastic piping we know.

I'd say that now the question is not if we can create laminar flow, but "Can we create directional flow that does not allow particles to linger in the water column, distributes the CO2 well, and does not leave stagnant areas?"

It's pretty amazing how the Japanese have solved all of that (and more) with the Lily pipe.

--Nikolay
 

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Another great thread to read through. A question that comes to mind when reading about the Lily output placement and co2 dispersal is how it changes when we diffuse inline with the filter output. It's been discussed that the Lily pipes are sometimes placed in certain places to pick up co2 from the diffuser on the opposite wall, but how does an inline reactor change things (if at all?)
 

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Interesting stuff!

I have a 15 gallon tank with one of those Zoomed 501's, which I thought was not providing enough water movement and allowing surface scum to build up. I am going to play around with the placement of the intake and outflow tubes while removing the spray bar for a singular outlet. This should be interesting to see what kind of "gyre" I can produce with this rather tiny and weak canister filter. I'll report back later.

Also, I have dead spots in my 65 gallon tank and have been worried that EI ferts weren't getting distributed evenly throughout the tank. I'll play around with it tomorrow as well.

David
 

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Here's a question that I've always wonders about. "how dead is a dead spot?"

Really, how dead IS a dead spot? O know, depends. I've always assumed that due to pressure variances in a tank water will circulate throughout. In "dead spots" that would mean slow movement, osmosis-like. But as long as there is good movement in the tank overall, isn't it likely that all plants get adequate exposure to co2 and ferz? They can only uptake so fast, so for plant health is a strong stream of flow in all nooks and crannies really necessary?

The benefit of deliberately eliminating dead spots then is just to keep detritus off the plants?

Just wondering. In my 84g i have had obvious areas of low flow, but the plants didn't seem to suffer.
 

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Here's a question that I've always wonders about. "how dead is a dead spot?"

Really, how dead IS a dead spot? O know, depends. I've always assumed that due to pressure variances in a tank water will circulate throughout. In "dead spots" that would mean slow movement, osmosis-like. But as long as there is good movement in the tank overall, isn't it likely that all plants get adequate exposure to co2 and ferz? They can only uptake so fast, so for plant health is a strong stream of flow in all nooks and crannies really necessary?

The benefit of deliberately eliminating dead spots then is just to keep detritus off the plants?

Just wondering. In my 84g i have had obvious areas of low flow, but the plants didn't seem to suffer.
There is a filtration benefit as well. The same bacteria that colonize your filter also colonize the substrate, plants and hardscape.
 

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AquaBarren,

First off, I'd like to say how cool it is to have someone who works in the fluid dynamics field in on this discussion! :whoo:

You've brought up an interesting point about pressure differentials. I'm sure they're a factor at some scale in our aquariums; but I don't believe they're significant on the large scale. The reason being, in such a small (even a large aquarium being small relative to nature) and enclosed system, our filters or other water movement devices tend to equalize pressure throughout the tank.

This also affects osmotic regulation or movement of chemicals in an aquarium. Relative to the small differences in pressure or concentration, circulation is so great as to make any osmotic gradients or pressure differentials insignificant, except perhaps at the plant-water boundary layer. I don't have any data to back this up; but I have observed greater plant health and growth in areas with stronger circulation vs weaker, in personal aquariums with non-uniform circulation.

"Dead spots" certainly aren't dead in the biological sense; rather, they're "dead" in regards to circulation. I've noticed a distinct increase in cyanobacteria and some algae in these dead zones. In my experience and opinion, what's good for algae is bad for plants, making dead zones a bad thing.

But as long as there is good movement in the tank overall, isn't it likely that all plants get adequate exposure to co2 and ferz? They can only uptake so fast, so for plant health is a strong stream of flow in all nooks and crannies really necessary?

The benefit of deliberately eliminating dead spots then is just to keep detritus off the plants?
[/quote/

1) For sure, good movement in the tank overall will increase exposure of at least some portion of a plant to suitable CO2 and fertilizer concentration. The trick is to maximze the area of exposure to keep the plant from removing nutrients from lower parts of the stem which causes a whole host of issues.

2) True, plants can only take up so fast, but they will deplete nutrients from slow moving water more quickly than it can be refreshed. Again, the trick is to maximize circulation of nutrients to as much of the plant as possible. In slow or no current areas plants will create an osmotic gradient which transports nutrients toward the plant. However, fresh, nutrient rich, circulating water is a stronger source of input than osmosis.

3) Eliminating dead spots is therefore, not only good for keeping detritus off plants.

Hope this helps,
Phil
 
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