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Growth retardation caused by flow?

I guess that flow issues in high tech tank are a more common issue than suspected. The thing is, a tank is much to 3 dimensional to say something conclusive about it from a picture.. In a closed system water flow is never liniar it not only bumbs in and back off the glass also the rocks, driftwood and plants themself have impact on flow behaivor. Plants are dynamic and change in shape and size flow changes also according to that. The filter slowly clogs and reduces flow, even if it is minimal it can have impact on dead spots moving to an other area.

Water is in principle and in behaivor the same thing as air only much denser and it is hard to predict or to see how it will move around objects. To get a beter understanding in theory and to a certain degree in practice how water behaves around objects than look up aerodynamics, how wind behaves for example in meteorology, for example wind falling over a tree and what happens behind the tree. This data is more common and easier to find than about hydrodynamics. Hobby aeronauts use this data and knowledge to fly safely from one spot to another. Not that it is necessary, but just to get an idea in your imagination what happens when water hits objects in your tank. And where would the vortex be and where the dead spots might be. And get a beter understanding in which direction to change the flow. 🙂

The only thing you can do is change it and wait a long enough period for the results.. If it still not improving after trying about all there is to try it still can be something else causing it.
 
Failing that throw yourself down the outdoor rapids at Centre Parcs...feel the hydrodynamics 😉
 
Show us a closer image of the HC? If its growing upwards, increase CO2. and increase surface agitation .And observe for 2 weeks with repeat pictures to compare .
 
rebel said:
Show us a closer image of the HC? If its growing upwards, increase CO2. and increase surface agitation .And observe for 2 weeks with repeat pictures to compare .
Click to expand...
Here's a close-up pic of the left side where I think the flow is not fine. The pic beneath you see the difference between the left and right side.
When I look at the plants myself, now I see traces of shortages. :wideyed:
But the strange thing is that everything grows fine everywhere, except in one spot.
01.jpg
 
As said you view it kinda liniar, like it hits the side and its pushed straight down in a 90° angle till it hits the bottom and then goes 90° back over the substrate.
flow-jpg.jpg

But it doesn't work like that, if water hits and object its pushed in all directions, starts to tumble and swirl, it creates a vortex. It doesn't do this up and down, but in any available direction. That's why it is so hard to explain in a flat 2D picture.. And when it bounces aff the side pannel swirling it hits a rock, that water again starts to swirl in an other direction counter acting on it's originating source.. 🙂 In between all these swirling pockets are dead spots constantly tumbling around it's own axis.
flow.jpg

Something like this..
Naamloos.jpg

The problem is you do not see it, but it definitively is there.. 🙂

It's the same as flying through the air and everything starts to shake like mad.. Thats turbulence, all caused by air pockets/fronts pushing against eachother and counter acting eachother.. In between these occlusion fronts there wll be still pockets doing nothing. In an aqaurium these fronts are created by static objects as long as the flow speed doesn't change these fronts dont change so also the still pockets stay where they are. 🙂
 
Cor said:
Here's a close-up pic
Click to expand...

upload_2018-7-13_17-8-29.png

Maybe the rock with the red 'X' is creating a bit of a dead spot to the left of it as the pressure of the water will be more on the left of the rock compared to the right, it doesnt take much! can the rock be removed easily for a few weeks ?

Edit had started to write then Phone call and Zozo got in 😉
 
zozo said:
In an aqaurium these fronts are created by static objects as long as the flow speed doesn't change these fronts dont change so also the still pockets stay where they are. 🙂
Click to expand...

Makes sense :thumbup: Looking forward to the Varible speed Maxspect Gyre all the more 😉
 
It's more the case that the co2 isn't being delivered to that part of the plants by your flow.

Easiest way to know where the dead spots are where the crap builds up. You should also be able to see the HC slowly moving in the flow when you get it right.

If you move your co2 bubbler to below your lily pipe you should be able to see small bubbles flying arround. It should also improve things.
Corners will naturally form dead spots but the front rock won't help. At the slow speeds were talking about in our aquariums the path tends to be a bit softer. Quickest way to make a big change is to move the lilly pipe and intake pipe.

sketch-1531976021320.png
 
I use an inline diffuser and the CO2 is adjusted with a pH profile. It is stable and has a value of 30ppm. So I expect the problem is related by the power of circulation. I use an EHEIM eXperience 150
and it has a capacity of 500 L/h. My tank is 50 liters. It looks like the flow is bounced through the glass and then to rise up against the stone through the bottom.
Perhaps the flow at that location is too strong for the plants to use the food and/or CO2because they simply go through the water too quickly?
I try to adjust the direction of the flow by directing it diagonally towards the front Maybe it helps, time will tell.:thumbup:
TOP.png
 
I'm too impatient too wait that long.

The faster the flow the less it will slowly bend around corners and the more it starts to bounce off objets.
With reference to the pictures earlier if you imagine a gentle river flowing around a Bend and compare that to the white water photo.. at that speed it travels in a straight line till it hits the next rock.

The higher flow won't stop you getting dead zones areas where the water stagnates like a 3d eddy in a river, but you have the power to drive the co2 to the bottom of the tank and get it circulating.

See the picture below.
swirling-eddie-in-the-clackamas-river-mount-hood-national-forest-cascade-AXDH13.jpg

Make yourself some tell tales with some thin strips of plastic bag with weights on the end. Other option would be some wool or something that naturally sinks on the end of something like a fishing pole.

Before long you should get a good idea what's happening.. it's a bit of a black art, chances are you might move the problem to else where.

There is a great video that I think cegg posted with all the plants gently swaying.

I'm running a 4000lph pump and setup in a 300L tank, plants like my Monte Carlo definitely grow in the direction of the flow. I'm sure there is a point where the higher flow causes more co2 loss through surface agitation, also delicate plants will start to get damages . But I suspect were along way from this point.
 
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