# Flow question, spraybar and lily pipes... once again?



## parotet (24 Apr 2014)

Hi all

Probably something that has been already discussed... My question is about the difference between the kind of flow produced by a spraybar or a lily pipe. I have a 65 liters (60 cm long) tank with two redmoor islands and the typical path in between. I also have a spraybar on the rear all along the 60 cm just some cm under the water surface, good co2 profile, EI ferts, 10x filter with little media volume, etc. 

Some pictures: http://www.ukaps.org/forum/threads/2.30758/

Actually the scape was even simplified some days ago, getting rid of a branch that was going upwards on the right side with some emerged plants... I was not happy with the flow even with a nano Koralia under the spraybar placed in the center. The problem is that these redmoors are really a flow barrier, especially for the lower leaves of the plants just behind (on the background) and the consequence: some small patches of BBA on the elder leaves less exposed to water movement. 

A spraybar all along the back let the water jets impact on the front glass, it makes the water go down and then go from the foreground to the rear... But in my case, the water finds a barrier. And yes, the plants parts that suffer BBA are just the ones behind this barrier. I have been told in my LFS that the wisest option would be to come back to the lily pipes. Placing the outflow on the right front side will create a circular flow (if looking from above it would be a kind clockwise movement) so it would a way of sorting out my two islands problem as the flow wouldn't find any barrier, but will turn around the barriers. But do this circular flow move the whole water column (36 cm heigh)? What I really need is to have flow on the bottom parts, both on the foreground (to keep a healthy Eleocharis carpet) and background (my stems plants on the background are healthy once they surpass the redmoor height thus receive enough flow) and I am not really sure if the lily pipes will move also this bottom water layers...

Jordi


----------



## NC10 (24 Apr 2014)

I've placed my spraybar just above the the substrate on the back wall firing up because of wood/obstructions which would have stopped the flow in the normal position. (top back firing forward) The flow is perfect, so maybe could work for you?

As soon as it hits the surface there's no where to go, so then carries on towards the front glass and then down, just as with the normal placement, but because it's behind the obstruction I'm still getting the flow where I wouldn't have using the usual position.

Also, because the it's on the bottom it's effectively sucking water along the substrate from the front as it fires up. It's a nice round and round flow is basically what I'm getting at


----------



## Tim Harrison (25 Apr 2014)

I think you've kinda answered that one yourself. I suppose that for many the choice is purely aesthetic, but in many cases, like yours, it's the scape that determines which is best in terms of achieving the best all over flow. Don't forget you can get different lily pipes that direct flow in different ways as well, e.g. across the surface, and down toward the substrate and practically everything in between. 
In the case of my latest scape, Tulgey Wood, a spray bar wouldn't quite cut it for similar reasons to your own, so I'm using lilly pipes that push a concentrated flow across the surface, against the opposite tank side, and crucially down along the substrate (for the carpet plants), and for that matter everywhere else in a complex circulation pattern. For me, it works very well.


----------



## parotet (25 Apr 2014)

Thanks NC10 and Troi, I have just tried my lily pipe outflow again but honestly with the spraybar I can see much more movement in all my plants. Placing the lily pipe outflow in the back or in the front I can easily see some dead spots (plants that don't move at all, probably because the model I have is not the right one?). I'll see how it evolves this week now that I have simplified the wood hardscape...

Jordi


----------

