# Fluval Spec question



## CHRISW (May 25, 2011)

I have my Fluval Specs each set to minimum flow at the pump.
The output current is still too strong for HM Bettas.
Have attached a small cut out foam filter to the output nozzle and was able to restrict the current flow.
If I were to reset the pump to Maximum for optimum tank filtration, will it stress the pump motor and damage it?


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## Tarobot (Jun 27, 2010)

should be ok ive done the same thing myself on the spec and several other filters as well.


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## mcrocker (May 29, 2010)

This is only a theory:

My observation is that just about any type of filter that has a form of flow control will do it by restricting flow at some point rather than adjusting the power or speed of the impeller. Therefore, if you have achieved a flow of X gallons / hour by throttling it somewhere in the system, it shouldn't really matter if it's being done by something you have added on the output or something designed into the filter system.

If you turn up your flow rate to achieve more filtration, you will either see no change since you already restricted the flow somewhere, or you will find you need to restrict it more since flow has increased, throwing off your careful tuning.

If your foam baffle thing is working by diffusing the current rather than reducing the flow rate, this would not be true and you may gain filtration by turning the filter back up in speed.

Am I making sense here?


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## Captured Moments (Apr 22, 2010)

I think it makes sense if I am reading it right but that's quite a chew. In theory it is not a good idea to restrict flow on the output side of a pump because by doing so will create resistance. Resistance to flow on the output side of a pump increases back pressure against the pump impeller. Pressure is greatest at the source point rather than at the point of obstruction. This will make your pump work harder, warmer, maybe shortening the life of it. 

In practice I don't know if it really makes a big difference in the life span of the pump. Anyhow I would look for a way to diffuse/soften the output flow while maintaining the normal flow rate rather than restrict it. You need to consider how much water you need to pass through the filter every hour to maintain efficient filtering. If you restrict the flow, you most likely will loose some of flow rate.


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## CHRISW (May 25, 2011)

Hagen Support's response to my email has confirmed that placement of filter foam on output nozzle would not stress the pump.
I have therefore, adjusted the pump to maximum for optimum filtration.
Current flow on max setting still seems to be ok for the HM bettas.

Thanks


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