# Water circulation and lily pipes



## Cbugeja (Jan 19, 2015)

I have a 30 litre nano tank (30cmx30cm base with a height of 35cm) with a pump that churns out 300 litres per hour (turnaround of 10 times an hour). As it is right now the flow is way too strong and I have to reduce it physically by stuffing glass wool in the nozzle, yet still the water jet is too strong for the plants and fish (5 harlequin tetras, 1 dwarf gourami and 3 endlers).

I will be moving my pump and filter to a sump under the the tank and was thinking whether using a lily pipe would make the flow any more bearable without having issues with circulation, i.e. that it does not throw the plants horizontal, and fling the fish against the glass.

I recently heard about the lily pipe spin... what can you tell me about it especially with regards to circulation in a small tank?

Thanks a lot in advance!


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## Apistia (Sep 28, 2014)

have you thought of DIY'ing a spraybar? that way your flow is metered out into the tank across 2 or 3 dozen drilled holes in a pvc pipe. it may not reduce your actual volume over time moved by the pump but it will spread the flow across a much greater area.


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## Cbugeja (Jan 19, 2015)

The spray-bar is something I might consider as well... I might get hold of some clear acrylic tubing so that the spray-bar would not be so visible, and would place it underwater so as not to disturb the surface too much due to CO2 injection. 

Although I would need to be sure that I have no dead spots of circulation.


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## Dead2fall (Jun 4, 2014)

Cbugeja said:


> The spray-bar is something I might consider as well... I might get hold of some clear acrylic tubing so that the spray-bar would not be so visible, and would place it underwater so as not to disturb the surface too much due to CO2 injection.
> 
> Although I would need to be sure that I have no dead spots of circulation.


Clear will get nasty quick and look worse than a normal spray bar. I'd paint pvc black or whatever comes close to your background.

Another option is it get some sort of mechanical clamp like a small u-bolt and pinch off your return tubing some to restrict flow. Eheim makes a product like this but I don't see paying all that money for it when a simple u-bolt would do the same.


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## Kathyy (Feb 22, 2010)

If you put your pump into a sump so it is an open system you will lose liters per hour due to head and plumbing losses. Do that first, maybe that is all that needs to change. My Rio pumps come with a ball valve. I put that on the return tubing and can turn down the water moving through if I like.

10x isn't too much water. Change the return so it flows across the top of the tank near the front with the intake on that same side. That mimics stream current with fast water near the top and slow water returning to the intake near the bottom. Have the return as open as you can get it so lots of water is moving through but at lower velocity. If there is a squeeze in your nozzle first try just removing it it see what you think. Some lily pipes are designed to reduce velocity as well but they shouldn't reduce flow.

If you must have the return at the back of the tank then a spraybar at the top across the whole back is best but you will lose some flow. Have it below water surface facing forward. People who are using canisters need to be careful that evaporation doesn't cause splashing which can half empty the tank. Since you are using a sump then evaporation takes place there and your display tank will always be full.


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## Cbugeja (Jan 19, 2015)

Kathyy... you got some interesting points there!

I am not worried too much about the flow, but about the velocity yes... maybe I didn't make that clear enough. 

Right now the water comes out of the pump about an inch from the surface and it still creates a huge current... so strong, that as soon as the fish stop swimming, they are half way around the tank in less than 5 sec... true it is a very small tank... but still they make me smile as they end up as if they were on a carousel 

Your point about the losses due to plumbing is interesting... hadn't thought about that. 

Re lily pipes: do the standard lily pipes really make a noticeable difference when it comes to reducing velocity?

Bump:


Dead2fall said:


> Clear will get nasty quick and look worse than a normal spray bar. I'd paint pvc black or whatever comes close to your background.
> 
> Another option is it get some sort of mechanical clamp like a small u-bolt and pinch off your return tubing some to restrict flow. Eheim makes a product like this but I don't see paying all that money for it when a simple u-bolt would do the same.


Thanks... the u-bolt idea is interesting... cheap and cheerful!


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