# Spray bar with 2 canister filters?



## bcdudley (Nov 18, 2009)

I think I would just have 2 separate spray bars, or perhaps split it down the middle with a divider. Building a spray bar is pretty easy and I see alot of people over think the holes and diameter of the tube. Just make up whatever you want and the water will come out. The smaller and fewer the holes, the more pressure it will come out with. I would start out with some really small holes spaced evenly, then just go from there. If it seems like the pressure is to high or more than you are comfortable with, make more holes or bigger holes.


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## tyler79durdan (Jan 23, 2010)

You should use a diameter of pipe slightly larger than the ID of the return line. I think the 05 series fluval use 3/4 ID hose, so you'll want 7/8 OD pvc or close to fit snug in the hose. I would space the holes 1-2 inches apart and use a marker to trace a straight line down the PVC. given an area of about 0.60132 inches squared, and the area of your drill bit is 0.01227 inches squared, you should use 45 1/8 holes in a 7/8 PVC tube for a slight pressure increase within the spray bar... pi times radius2 equals area of a circle. I would only use one canister... but you will need a longer spray bar of at least 63"... or a bigger drill bit...


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## tyler79durdan (Jan 23, 2010)

bcdudley said:


> I think I would just have 2 separate spray bars, or perhaps split it down the middle with a divider. Building a spray bar is pretty easy and I see alot of people over think the holes and diameter of the tube. Just make up whatever you want and the water will come out. The smaller and fewer the holes, the more pressure it will come out with. I would start out with some really small holes spaced evenly, then just go from there. If it seems like the pressure is to high or more than you are comfortable with, make more holes or bigger holes.


Poor advice dude! This is not a guessing a game. It is a math equation with a definite solution.


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## tunerz (Sep 21, 2009)

If it works out, do a tutorial for us.


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## GTR (May 27, 2009)

My thoughts...

Two spray bars if you have two filters. It will be easier to control and easier to do maintenance. I'm not sure my Rena's disconnect could handle the pressure if one was disconnected and the other still running. I think the opposing forces at the center of the pipe will increase head pressure and reduce flow. Might not be much more than a hard 90° but some loss anyway.

Not all holes should be drilled in a straight line since you may want to direct flow to a different area based on where you plants are inline with the output.

Paint the PVC or use gray.

IMO this question can't be determined via mathematical equations and lucky for you PVC is cheap. lol

SteveU


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## tyler79durdan (Jan 23, 2010)

GTR said:


> IMO this question can't be determined via mathematical equations and lucky for you PVC is cheap. lol
> 
> SteveU


Explain how the surface area of a circle can not be divided by the surface area of a smaller circle and tell you how many holes will fit into the larger circle???????????????

Also if you reduce the number of smaller circles(holes) within the larger circle, the voided area would increase the pressure in the bar.

Holes in a straight line are by far easier to control the circulation within a confined area.

Simple math!


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## GTR (May 27, 2009)

tyler79durdan said:


> Explain how the surface area of a circle can not be divided by the surface area of a smaller circle and tell you how many holes will fit into the larger circle???????????????
> 
> 
> Simple math!


Determining the optimal number of holes to deliver the desired pressure isn't the same as how many you can jamb in there.



tyler79durdan said:


> Holes in a straight line are by far easier to control the circulation within a confined area.


I'll just have to disagree if that's OK. I have two spray bars, one of each end of the tank. One has one hole pointing up at the surface just enough to ripple the surface. Three holes toward the front are pointing down towards the substrate. Three holes towards the back are pointed more at the side wall to help defuse the pressure so it rolls back at the bottom to supply the stems along the back wall. The other end has something similar but I needn't go into the particulars to make my point to the OP.

SteveU


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## Guns286 (Sep 17, 2009)

Lot of good advice. Tyler, mathamatics can probable figure out anything. Unfortunatly, my 4 year old is better at math then I am. So, I'm going to need you to explain it to me as if you're explaining it to a child.
Other then that, it seems like my 2 choices are splitting the spraybar in half and using 2 filters, or one long spraybar and 1 filter. What if I split the return from the Fluval and run each into the opposite ends of the spraybar? Would'nt that help with a more even distribution? Then I could reduce or increase the size/amount of holes, in order to regulate water flow.


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## GTR (May 27, 2009)

From what you're saying it's sounds like you want more or better circulation. I think a surefire way of getting that is adding another canister. I couldn't get what I wanted for my 90g with a single XP3 and I don't care for powerheads in the tank.

SteveU


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## tyler79durdan (Jan 23, 2010)

GTR said:


> Determining the optimal number of holes to deliver the desired pressure isn't the same as how many you can jamb in there.
> 
> 
> 
> ...


Ok, I agree to disagree 



GTR said:


> From what you're saying it's sounds like you want more or better circulation. I think a surefire way of getting that is adding another canister. I couldn't get what I wanted for my 90g with a single XP3 and I don't care for powerheads in the tank.
> 
> SteveU


+1 on the second canister, but make two spray bars.

Give my the inside diameter of the tube(bar) and the desired length, and I will tell you how many holes to put in the bar, and bigger holes does not regulate flow... thats what the aqua-stop does.

You HAVE to have an increase in line pressure within the bar to get each of the holes to deliver an equal stream/jet of water.

I guess you should also decide if you want a staggered hole pattern as Steve suggests, or a straight line as ALL spray manufactures use. This is a matter of experience and opinion.

I have made numerous spray bars, and ALL of them have had required pressure to flow almost max canister flow rates, and still have VERY even streams from each hole using a simple math equation.:wink:


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## Guns286 (Sep 17, 2009)

Figure 2, 21" long spray bars. I'm getting 3/4", clear, Schedule 40, PVC pipe with an ID of .824 
I'll run them vertically, along the back, top of the tank. I planned on making the holes in a streight line. 
OK professor, what do you think


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## GTR (May 27, 2009)

The professor has taken leave. I'm hoping our little discussion and differences in opinion had nothing to do with that, seriously. If everyone thought the same and did things the same way keeping a tank would be like painting by numbers.

Those differences are what keeps it interesting. JMO

SteveU


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## wkndracer (Mar 14, 2009)

*Ugh! I hate math.*



Guns286 said:


> Figure 2, 21" long spray bars. I'm getting 3/4", clear, Schedule 40, PVC pipe with an ID of .824
> I'll run them vertically, along the back, top of the tank. I planned on making the holes in a straight line.
> OK professor, what do you think


_"tyler79durdan; You HAVE to have an increase in line pressure within the bar to get each of the holes to deliver an equal stream/jet of water."
_
This is valid flow/back pressure information. Without a slight loss of free flow volume the end of the tube will see less discharge through the bar holes.
_"__tyler79durdan; __pi (3.14) times radius2 equals area of a circle"_

Using 3/4" id pvc I came up with a different number. (.44156) 
Using 1/8 drill bit (calculation +- rounding error same as tyler79durdan) at .01227 = 35.987 or 36 holes needed to equal the total area of the spray bar inlet to total outlet.

So using 35 - 1/8" holes and allowing for a slight back pressure (less discharge then inlet volume) 21" pipe less 1" (for hose clamping 1/2" and 1/2" end capping) 20"/35 = one hole every 1/2" +- at one every .57".

Whether the holes are drilled inline or rotated around the bar in different directions would make no difference as area volume in still equates to total area volume out.
Using a larger drill bit would mean less holes and increased spacing between them.

I hope what I've typed out make sense in the post because the math is valid in a very basic flow calculation.
LOL garbage in always equals garbage out :wink: minus the frictional loss as the poo goes around the corners.

http://www.mathgoodies.com/lessons/vol2/circle_area.html


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## Landau (Mar 24, 2010)

*To all the math whizzes out there*

Don't forget boundary layer effects. Because of increased turbulence and drag at the edge of the hole or tube you can not determine this stuf by the area of the hole alone. 

One 1 inch tube will carry more flow than four 1/2 inch pipes because of this. The amount of this differnce depends on the density and viscousity of the fluid, so it would be more pronounced in salt water than fresh. It turns out not to be such a simple math problem. If anyone still wants to do the math, I have my fluid mechanics text books from university for sale.

I'd go with the start with holes smaller than you think you will need and work up from there method.


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## Guns286 (Sep 17, 2009)

WOW! Guess I should have paid attention in physics class!
Thank you wkndracer, you gave me a clear and easy to understand answer. Does what Landau said make a significant difference? Will drag effect the flow that much? I cant imagine making the holes smaller then 1/8". If I wanted to start off with less, could I do a 1/8" hole, every 1" instead of every 1/2"? Help me out guys! I'm drowning in mathmatics!!


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## wkndracer (Mar 14, 2009)

Guns286 said:


> WOW! Guess I should have paid attention in physics class!
> Thank you wkndracer, you gave me a clear and easy to understand answer. Does what Landau said make a significant difference? Will drag effect the flow that much? I cant imagine making the holes smaller then 1/8". If I wanted to start off with less, could I do a 1/8" hole, every 1" instead of every 1/2"? Help me out guys! I'm drowning in mathematics!!


Actually what he posted was you may need larger holes then 1/8" and yes what he said makes sense but at an engineering level. I work in a dual 750 megawatt power plant with steam boilers. Boundary layer effect is why the inside of the tubes in the water walls have a spiral winding very similar to rifling in a gun barrel. But enough of this and that. What your doing is making a spray bar for an aquarium filter discharge. Start with 1/8" holes and just try it. If the water sprays out with too much force or you feel it's bogging down your filter flow just re-drill to larger size holes. (I would not start 4x larger then the simple math first) 
I've verified flow on my canisters simply by observation on water change day. With the tank a few inches short of filled (spray bar above the water line) crank up the filter and see how far and with what force the discharge sprays. If you feel like it's stronger flow then you want drill the holes bigger.

I purchased one of the Tom Aquarium Products Flow Meters when I was putting my sump system together but never used it.:iamwithstSump pump keeps up with the drains and the tank stays clean so I don't care. (never opened the packaging so it was money wasted)

Landau, agreed there's more to it but what the heck, if the OP doesn't hit it spot on the first time we're talking about 42" of 3/4 PVC (cheap) and at worst case scenario a Saturday afternoon spent tuning the flow by re drilling the holes. I have here on my desk the McGraw Hill eighth edition Engineering Formulas by Kurt and Reiner Gieck. :biggrin: I'm not opening it for this post either so you can keep your text books I have enough heavy reading as it is. (but thanks for the offer)

IMO, (as all posts are) I'd drill that sucker and try it.:icon_wink


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## Guns286 (Sep 17, 2009)

Sound good to me. Thanks for the help. I'll give it a try and let you know how it goes.


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## bcdudley (Nov 18, 2009)

Wow. I built my spray bar several years ago and just guestimated like I described. It has been working great since I built it. My pump is still working good and I have even upgraded to a bigger pump without changing any of the holes. Maybe I just got extremely lucky the first time around and drilled the exact number of holes at the exact size needed and the exact length needed... all on a guess. Or Maybe it just isn't as precise as said and you can get away with pretty much whatever you put on there as long as there is not to much back pressure.

You can call my advice poor advice if you want, but I can say the same about yours. You are way over thinking this project. A pump will pump a certain amount of water based on the amount of back pressure applied to it. Back pressure can be caused by multiple factors including the height of the tank, the size of the hose, the number and size of the outlets and the amount of debris in the filter. If the number and size of the holes were so precise, then manufacturers would have to sell a different pump for tanks of different heights. You would also see alot more pumps burning out faster because of the tighter tolerances. Pumps are designed to handle a wide variety of scenarios. Don't believe me, look at the back of a pump next time you are at a store and you will see a chart on the back with the gps at different heights.

This is not rocket science. Grab some pvc pipe, start drilling till you find something you like. If you think my advice is poor advice, piss off and don't read it.


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