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Water flow in the planted aquarium?

ceg4048

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Hello,
Thanks for providing the images. That makes it very easy to understand the question.
It will require som experimentation no doubt, but I would start with a scheme based on Setup 3.

It may not be necessary to mount the spraybar in the center. First of all that might look a bit strange and it might require some imagination to mout it and to route all the plumbing.

What has worked to some degree in corner and triangle tanks is to move the bar towards the rear wall, just about where your red blob is. Although it may not span the entire width across the hexagon, the flow will tend to be a bit more uniform (I think).

Not having played with hexagons, I'm not 100% certain, but definitely that is the logical starting point.

Again, don't spend a lot of money on materials. Use cheap PVC and drill the holes, or find the cheaper Fluval or Eheim green spraybars and cut them to various sizes.

Cheers,
 

Jason Blake

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1 Sep 2014
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58
Thanks for the response. I appreciate it.

Yes, odd shape tanks are the bane of my life, but this tank was giving to me for free, so as they say you shouldn't look a gift horse in the mouth.

That being said though if I can overcome the shape barriers I think it could look good.

Thanks again.
 

Luis Batista

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Portugal
Let´s hear some expert opinion about what i did.
My filter hose is 12mm inside.
The pvc pipe is 12mm inside also.
The pvc pipe is 82cm long to a 100cm tank.
Each hole is 2mm diameter and i drill 9 holes.
I have a bit more pressure in each hole that with the stock 20cm spraybar with 5mm holes and have a nice surface agitation.
I try do do the math with the diameter squared but get lost really quick :what:.
By that equation, am i close to it or not?


Thanks all
 

ceg4048

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Sorry Luis but that video makes me nauseous. There is too much motion.
Do you have a tripod? It''s also overexposed when you point it near the lights. Very painful viewing on my monitor.
In any case, it would be better to drop the level of the water so we can see the individual jets.
Also you need to look at the plant leaves to see if they are moving at all locations.

Cheers,
 

NC10

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Let´s hear some expert opinion about what i did.
My filter hose is 12mm inside.
The pvc pipe is 12mm inside also.
The pvc pipe is 82cm long to a 100cm tank.
Each hole is 2mm diameter and i drill 9 holes.
I have a bit more pressure in each hole that with the stock 20cm spraybar with 5mm holes and have a nice surface agitation.
I try do do the math with the diameter squared but get lost really quick :what:.
By that equation, am i close to it or not?

Thanks all

12mm ID works out at an area of 113.1.

A 2mm hole works out at 3.14.

You've drilled 9, so 9 x 3.14 gives you a total of 28.26. That's way down on where you should be so you're going to be restricting a lot of flow.

If you just re drill the 9 holes you already have with a 4mm bit, it will give you 113.13 which is pretty much bang on.

Hope that helps.
 

Luis Batista

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19 Jun 2014
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12mm ID works out at an area of 113.1.

A 2mm hole works out at 3.14.

You've drilled 9, so 9 x 3.14 gives you a total of 28.26. That's way down on where you should be so you're going to be restricting a lot of flow.

If you just re drill the 9 holes you already have with a 4mm bit, it will give you 113.13 which is pretty much bang on.

Hope that helps.
Thanks NC10

that is the help that i need

Thanks alot

Enviado através da ponta dos meus dedos!
 

Luis Batista

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19 Jun 2014
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Location
Portugal
12mm ID works out at an area of 113.1.

A 2mm hole works out at 3.14.

You've drilled 9, so 9 x 3.14 gives you a total of 28.26. That's way down on where you should be so you're going to be restricting a lot of flow.

If you just re drill the 9 holes you already have with a 4mm bit, it will give you 113.13 which is pretty much bang on.

Hope that helps.

Can you explain how you get that numbers 113.1 and 3,14?
i must not be the only one that dont understand nothing from this equation...

once again, thanks NC10!!!
 

NC10

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Can you explain how you get that numbers 113.1 and 3,14?
i must not be the only one that dont understand nothing from this equation...

once again, thanks NC10!!!

The easiest way is to just put your info in here: https://www.google.co.uk/#q=circle area calculator

Don't forget that you use the radius to work the area out and not the diameter. So for 12mm ID you would put 6mm in.

Do the same for whatever size holes you want and just multiply the holes until you're close enough to the total area. Just play around with different combos of hole size and number until you're happy. In your case though, 9 x 4mm holes is as perfect as you'll get.

Let me know if you need any more help.
 
Last edited:

Luis Batista

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Portugal
Area is pi R squared.

So R is 6mm in first case, the A = pi x 6 x 6 = 3.141 x 6 x 6 = 113 mm2.
Where do you get the 6mm?

Enviado através da ponta dos meus dedos!


EDIT: its the radius of the hose right? If the hose were 20mm ID it will be 10 in the equation?
 

ian_m

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R is radius of circle, which is half the diameter.
3595454_f260.jpg
 

Luis Batista

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The easiest way is to just put your info in here: https://www.google.co.uk/#q=circle area calculator

Don't forget that you use the radius to work the area out and not the diameter. So for 12mm ID you would put 6mm in.

Do the same for whatever size holes you want and just multiply the holes until you're close enough to the total area. Just play around with different combos of hole size and number until you're happy. In your case though, 9 x 4mm holes is as perfect as you'll get.

Let me know if you need any more help.
With that 14mm my brain started to melt again bit i saw that must have been a mistake...
Thanks NC for all your help

Enviado através da ponta dos meus dedos!
 

Luis Batista

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Its better to let it be with 9 holes and just make them 4mm or stay with the 2mm ones and drill another 9 holes?
In the end the area will be the same and more holes perhaps was better to get all places in the tank.
Or like MG ex wife said im a very complicated guy?

Enviado através da ponta dos meus dedos!
 

NC10

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No it wouldn't work like that.

2mm area is 3.14 and 4mm area is 12.57 and not 6.28 like you would expect.

Easiest is just to make the existing holes 4mm, or start again with a new spray bar if you want a few more holes......or you could drill 36 holes in total at 2mm to make up the area. Seems a lot though.
 
Last edited:

Luis Batista

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No it wouldn't work like that.

2mm area is 3.14 and 4mm area is 12.57 and not 6.28 like you would expect.

Easiest is just to make the existing holes 4mm, or start again with a new spray bar if you want a few more holes......or you could drill 36 holes in total at 2mm to make up the area. Seems a lot though.
Just finish drilling it with the 4mm holes.
All the pressure that i had from the 2mm holes are gone but now it seems that the water dont have enough pressure to hit the glass and go down to the ground...
Lets see...

Enviado através da ponta dos meus dedos!
 

foxfish

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I am not convinced by this theory, I just don't see how it can work in the real world as the individual pump performance & head rating will effect the strength of the jetted water?
I can see how the calculation is done but personally I would drill several trial bars until you get the best performance.
 

NC10

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I am not convinced by this theory, I just don't see how it can work in the real world as the individual pump performance & head rating will effect the strength of the jetted water?
I can see how the calculation is done but personally I would drill several trial bars until you get the best performance.

I think all it comes down to is keeping the flow as it was originally intended, regardless of pump or flow rate. You can't take head into account really because everyone's pump is going to be different heights anyway and even a cheapo pump still has a certain size pipework it's been designed for.

Sticking with the in/out theory should hopefully see the pump turning over near enough the same amount as if you just had it coming straight out of the end of the pipe, minus a little restriction from the spray bar holes of course.

Going less than area is going to hold the pump back, not really a problem if you've over spec'd it, but if the pump is solely providing the 10x, you're going to want to squeeze every last drop out.

Going bigger than area is going to affect the pump as well. You're going to start losing pressure.

Keeping the in/out the same just means you're losing minimal flow and performance IMO Changing the number and size of holes is how you can alter the flow or velocity to suit your setup, but still going along with the same area theory.
 

Luis Batista

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I think all it comes down to is keeping the flow as it was originally intended, regardless of pump or flow rate. You can't take head into account really because everyone's pump is going to be different heights anyway and even a cheapo pump still has a certain size pipework it's been designed for.

Sticking with the in/out theory should hopefully see the pump turning over near enough the same amount as if you just had it coming straight out of the end of the pipe, minus a little restriction from the spray bar holes of course.

Going less than area is going to hold the pump back, not really a problem if you've over spec'd it, but if the pump is solely providing the 10x, you're going to want to squeeze every last drop out.

Going bigger than area is going to affect the pump as well. You're going to start losing pressure.

Keeping the in/out the same just means you're losing minimal flow and performance IMO Changing the number and size of holes is how you can alter the flow or velocity to suit your setup, but still going along with the same area theory.
In my case i think that the best holes will be between 2mm and 4mm, 3 or 3.5mm.
With 2mm have a good water pressure but reduced flow.
Now with 4mm almost dont have any pressure, the first hole dont have any pressure, the water pass trow it and dont exit.
Tomorow will do another spray pipe with 3mm holes to see if i get a more balance between speed and flow...

Enviado através da ponta dos meus dedos!
 

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