DIY Fluval Flex 57l Spray bay

[philljoynes]

I have made the following spray bar for the Fluval Flex and thought that others may be interested. Thanks to @Andrew Butler for suggesting this PVC pipe method. I had used eBay 3D printed spray bars before and they had holes all over and did not work for me.



The thread on the Fluval Flex current setup is 1/2 inch BSP (I believe it technically is NPT), though I ended up not needing any threaded items. I purchased:

1 x 1/2 inch imperial grey (I could not find black) PVC pipe 2.5m (way too much, but it is cheap and allows testing)
1 x 90 Degree PVC Elbow
1 x End Cap

I found this post useful for getting a calculation to work out the holes.

I used the area of a circle calculator on Google:
For my 12mm Internal Diameter pipe the Area is about 113 mm2.
For a 4mm hole, the Area is about 12.5.
Now I divide the total area by the 4mm holes to figure out what size holes will allow the same flow and velocity 113 /12.5 = 9 holes required.

I have so much pipe and after reading the post above, I decided to make several different pipe holes and have settled (my own preference ended up on 10 x 3mm holes, to fulfil the calculation above it should have been 16). This may not work for you but with so much pipe you can experiment to find what works for you.

You can see from the following photo that rather than replace the whole assembly I just push the 90 Degree elbow onto the end of the ball joint, it works, gives you additional movement and can be removed allowing you to get the assembly off again to clean. There is no glue used with this and it is strong enough to stay together with just friction.



This post was very useful for me to understand the importance of flow and how the spray bar helped, I would highly recommend a read.

Since the installation, I can see the Lilaeopsis Novae Zelandiae carpet is looking healthier and the plants lower down and at the back like the Bucephalandra, Staurogyne Repens.

 

[Kevin Eades]

I will have to try this

 

[Valodia]

I think some of the specialized pipe e-shop selling clear pipes and fittings:
Cleal Pipes

The 3d printed ones sold on ebay are in my opinion not fit for purpose as they have too many or/and too big holes. Also the tube itself is thin - as a result it jets water at angle.

 

[philljoynes]

Thanks for the link to the clear pipes.

The 3d printed ones sold on ebay are in my opinion not fit for purpose as they have too many or/and too big holes. Also the tube itself is thin - as a result it jets water at angle.

I found this also when I tried one. The holes were not just straightforward, they were at three different angles which weren't conducive to good flow, it just pushed the water in different directions.

 

[idris]

I think some of the specialized pipe e-shop selling clear pipes and fittings:
Cleal Pipes

The 3d printed ones sold on ebay are in my opinion not fit for purpose as they have too many or/and too big holes. Also the tube itself is thin - as a result it jets water at angle.

I was interested in the clear pipes until I saw the price.
1m of clear 1/2" pipe = £10.69
3m of black from Toolstation = £1.48
For a clear 90° elbow, it's £9
For a black one from Toolstation it' £0.68
I think clear is an advantage as you can see when the spraybar is getting crudded up inside. (Maybe that doesn't happen in a better maintained tank than mine. 😳) But the price differential is hard to ignore.

Interesting about the wall thickness. I've used clear 22/16 acrylic tube (ebay). With its 2mm wall it's easy to see from the flow if you've not drilled a hole quite straight. But with holes spaced every inch or so, I'm not convinced that makes a significant difference to average flow across the surface of the tank.