# Anyone using a FX4? - How to calm it down?



## Lee_k (3 May 2021)

Hi all,

As per the title really - Is anyone running a FX4? and if so, have you got any tips on reducing the flow, i'm finding its just a bit too much for the plants blowing them all over! 

I did message fluval about half closing the valves on the in and out but they said that would cause damage to the pump!

The problem I have is the FX4 obviously has loads of flow (2650litres per hour is claimed!) but its from just 2 outlets near the top. So i'm finding the plants are being blown all over the place, yet lower down i'm getting like a black/dust/dirt/algae on the plants, alot of which I can dust/move off with hands so I was going to add a small circulation pump (Fluval CP1 maybe?) lower down in the tank to give some "low flow" and stop anything building up. 

But how can I reduce the FX4 a little? - there's no glass outlets etc for the fluval I can find which would improve looks and give a more "open" outlet to reduce flow. A idea i've seen is putting a sponge over the outlets but i'm not sure how this would look!

Any advice appreciated

Lee


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## EA James (3 May 2021)

I've got an FX4 on my tank, keep the in fully open and the out where you want. I have mine at about 3/4 out to slow the flow a little and its worked fine for the best part of two years. Strange that they would say not to when the make it so you can adjust the flow! 

What outlet nozzle has it got? I've got the duckbill on mine, one pointing up for surface agitation and the other down for flow. What size tank have you got?


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## John q (3 May 2021)

EA James said:


> Strange that they would say not to when the make it so you can adjust the flow!


I don't have the fx4 but on the 407 fluval recomend not reducing flow with the aquastop valve more than 50%. Being more specific, on fluvals fx faq it states this.

*How much can the flow of my FX-series filter be reduced via the AquaStop valves?*
You can safely turn down the output AquaStop by 50% in order to reduce flow without damaging the filter’s pump.









						FX SERIES - Fluval Canada
					

Another excerpt here...




					fluvalaquatics.com
				




So I agree with James its strange fluval would tell you not to slightly reduce the flow via the output.


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## Zeus. (3 May 2021)

Taking the Duckbill off will reduce the flow which is what I did once I went for Maxspect Gyres. Removing the duckbill increase filter output but produces next to no flow, which is what I was after with the Gyres fitted






Lee_k said:


> i'm finding its just a bit too much for the plants blowing them all over!


Which sounds like turbulenct Flow


Lee_k said:


> yet lower down i'm getting like a black/dust/dirt/algae on the plants



Which suggests poor flow at substrate level

Having a filter with a high output isn't enough and we need to convert the filter output into good flow in the tank 

I used DIY spray bar with my FX6




Lots of small holes which 'jets' and creates flow in the tank.

A DIY bespoke spraybar along the back off the tank would be my suggestion for a braced tank, or plumbing to convert from FX6/FX4 25mm hose to twin 16mm hoses and fit twin lilypipes if you have an open top tank without bracing, even than you will need to play around to see what works well, as it will be scape/planting dependant as well.
Spraybar along back is the one that would defiantly work, dont drill you holes to big lots off small holes worked well for me.


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## Lee_k (3 May 2021)

EA James said:


> I've got an FX4 on my tank, keep the in fully open and the out where you want. I have mine at about 3/4 out to slow the flow a little and its worked fine for the best part of two years. Strange that they would say not to when the make it so you can adjust the flow!
> 
> What outlet nozzle has it got? I've got the duckbill on mine, one pointing up for surface agitation and the other down for flow. What size tank have you got?



Its a 120cm x40cm x 60cm tank, its got the normal duckbill outlet with the 2 outputs



John q said:


> I don't have the fx4 but on the 407 fluval recomend not reducing flow with the aquastop valve more than 50%. Being more specific, on fluvals fx faq it states this.
> 
> *How much can the flow of my FX-series filter be reduced via the AquaStop valves?*
> You can safely turn down the output AquaStop by 50% in order to reduce flow without damaging the filter’s pump.
> ...



Yeah I thought thats what the marks on the valves were for but fluvals email back to me read:

"As for the FX4 we would not recommend reducing the flow, just try direct the flow upwards to the water surface."




Zeus. said:


> Taking the Duckbill off will reduce the flow which is what I did once I went for Maxspect Gyres. Removing the duckbill increase filter output but produces next to no flow, which is what I was after with the Gyres fitted
> View attachment 168059
> 
> Which sounds like turbulenct Flow
> ...



I have removed 1 of them and left the other currently trying to reduce flow but its like you say in that i need some flow lower down, thats why i was thinking of adding a small circulation pump


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