# What size and how many holes on Spraybar.



## Katfish (9 Nov 2012)

I am going to make a full length spray bar for my 6ft tank but unsure on how many holes I need and size to get a near even flow out of the holes.

The pipe is 15mm internal dia that I am going to use for the spray bar.

The pump supplying the spray bar is rated at 3400l/ph with a 16mm hose outlet.

Can anybody help ?


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## REDSTEVEO (9 Nov 2012)

Wow that is going to be some spray bar!! I am presuming that you are manufacturing this yourself from a 6 foot piece of pipe? I am no expert mate but I would say find an Eheim or Fluval Spraybar in a shop, count the number of holes and the diameters or size of holes and replicate this all along the pipe.

You will obviously have to block up the far end of the pipe with something. If you are drilling the holes yourself make sure they are all level and pointing in the same direction across the top of the tank or slightly downwards. Rotation of the pipe can also achieve this.

I assume your pump is strong enough to maintain the pressure to get the maximum water flow through the holes? If in doubt start by drilling smaller holes and less numbers to begin with. You can always add more holes or make them bigger but you can not make them smaller or take them away after if you have too many. A bit of trial and error by the sounds of things.

Let us know how you get on.

Cheers.

Steve


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## foxfish (10 Nov 2012)

Get some cheap B&Q overflow pipe & experiment first.. try 3mm holes every 75mm - use electrical tape to seal holes & a battery drill to gain more holes. You can just about push 16-22mm filter tube into overflow pipe use the tape to seal the end.


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## Stitch (11 Nov 2012)

Hi,

Your situaiton sounds similar to mine. I'm using an Eheim 2260 with the 1262 pump (3,400 lph) on a 1.5m tank. My spray bar is 1.3m long. I'd recommend reading my thread for more detailed information:
http://ukaps.org/forum/viewtopic.php?f= ... 10#p242117

By the way, I wouldn't go with a pipe with 15mm ID as this is roughly 7 or 8% less than 16% so you'd instantly lose a few hundred litres per hour. As was explained to me, you need to keep the diameter at 16mm or larger to maintain the maximum amount of water processed each hour.

As you can see in my thread I am stretching the 16/22mm tube over 1/2inch PVC. This has an ID of 18mm. So the outlet starts at 16mm and then goes into 18mm. The trick now however is making the total area of the spray bar holes equal 16mm. If the total area didn't equal 16mm then this is when I saw uneven spray / flow through the bar.

Clive gave me a formula for working out the hole size based on quantity / spacing, this is in my thread.

I've been playing around with various spray bar designs over the last couple of weeks. Initally I started with 33 holes (see videos in my thread). Since then i've tried around 4 or 5 different versions.

For me the best appears to be 26 holes at 3.2mm every 2 inches. Water is hitting the glass evenly and with plenty of force and there is movement all throughout the tank.

Also, I've noticed that the angle you drill the hole has a slight impact so try to drill the left side holes on a slight angle (coming in from the left), the middle ones square and the right on a slight angle (coming in from the right). It's hard though and you'll probably only see what I mean after you've made your first one.

Please update with your findings and some pictures.


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## DrRob (29 Jan 2013)

Speedfit stop ends fit nicely onto overflow pipe if you want an easily removable cap for your overflow.


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