Slowing Filter Flow Rate

The more I look at my filter (Fluval U4), the more I'm convinced I need to lower the flow rate. The tank has only just finished cycling so I dont have fish but the fish Im planning on stocking (fancy goldfish) dont really like a current and mine definately has quite a strong one. However, I need the large filter due to the amount of mess that they create.

I've ordered a cheap spray bar kit thats actually designed for older series 1/2/3/4 to see if it can be adapted to fit the U series but if not, then Im thinking I need to look at trying filter wool.

The question I have is, how do I actually add the wool to the filter to slow the flow rate? The three compartments are quite a tight fit inside the filter housing so Im not sure how it would fit. My next thought was to simply get some duct tape and close off some of the lower inlets on the case and if necessary, outlets. I know this would reduce the overall filtration rate but I think the reduced flow rate would be worth the trade off.

I saw a mod for betta tanks which involved taking an empty 20 oz. soda bottle (remove label), cut off the two ends so you just have a cylinder, and then slice that open, and attach to your filter outlet in such a way to obstruct and break up the current. Link has directions.

http/www.petfish.net/kb/entry/347/

Sounds like you have an application that this could work well in.

lol, thats pretty ghetto but the principle seems sound. Basically providing a flow disrupter over the outlet.

Not as ghetto as duct tape : )

Possibly, but at least duct tape is industrial

Im not sure if it would work on mine or not to be honest. The U4 has a venturi jet outlet at the top and it would need something quite resistant. Im not certain that the soda bottle wouldnt get jetted out of the way.

Using the soda bottle as inspiration, I've ordered a replacement pack of foam internals and the carbon/poly internals. Im going to first try and place the foam over the outlet to diffuse the water flow. The foam is quite open compaired to the carbon/poly pads therefore Im hoping that it will still allow the water to exit correctly and just diffuse it. The U4 has a spray bar option on the filter itself which takes the form of a horizontal column of smaller jets between a top and bottom venturi ouput. The idea is to trim the foam down a little and place it over this spray bar.

If that doesnt work, Im then going to attach the carbon or foam to the side intakes to reduce the rate at which water is drawn in. By increasing the stages that the water has to be pulled through, Im hoping it will reduce the input and thus the output rate.

Im generally just going to have a play around with elastic bands and foam pads to slow the flow rate. I'll post the results here once I receive the goods to help anyone else in the future who may have a similar problem.

Slowing your intakes might just burn out your motor. The classic way to reduce over-circulation is to figure out a way to point the spraybar streams at a tank wall. If there is concern about enough surface agitation and oxygen then still pointing at a wall but getting the starting point farther out in the tank is the approach, if possible.

Hope this helps with a few ideas.

~~waterdrop~~

A large piece of drift wood placed underneath the output would disrupt any current. I have a similar situation. I'd rather have the larger filter as well and that way I don't have to clean it as frequently. With my setup, there are frogs that hide underneath the drift wood because it provides a cave.

I could try the filter fitted to the front side of the tank pointing towards the rear to see if that helps but I have a feeling it would just change the current direction rather than the actually stregnth of it. The filter is about 30cm in height so its difficult to place something directly in front of it as it would pretty much reach from the bottom of the tank to the top.

JMcQueen said:

I could try the filter fitted to the front side of the tank pointing towards the rear to see if that helps but I have a feeling it would just change the current direction rather than the actually stregnth of it. The filter is about 30cm in height so its difficult to place something directly in front of it as it would pretty much reach from the bottom of the tank to the top.

Click to expand...

I am just setting up a 120 gallon, and this is what I meant about a piece of wood being used to break up a current. The filter creates a fairly substantial current but this piece of wood breaks it up. You can also throw on more attachment pieces to the end of the output that reduces the pressure a little bit, or throw on a UV Sterilizer or something like that. Anyway, there are a number of solutions.

With the Fluvals if you want to slow flow rate you can just place a finer sponge in replace of the coarse one they have. Of course if you have just cycled I doubt that will be attractive. Otherwise you can place some filter floss between the coarse sponge and poly/carbon insert and it will be slow and with time it will clog up a bit and reduce the flow. Of course when you're not too happy you can take it out an wash it. I did this on a Fluval U2 for some time and in fact still do as it just sucks fish into the corner of the tank otherwise.

acording to the manual, the flow rate can be adjusted.


"ADJUSTING THE WATER FLOW
The water output can be custom selected based on the desired flow. By simply rotating the
adjustable 3-way flow control knob you can select one of 3 output settings as well as
adjust the flow rate."

IIRC Fluval U series have a little screw above the water outlet and if you turn it, the flow rate is decreased.
Carl

Aqua Tom said:

acording to the manual, the flow rate can be adjusted.


"ADJUSTING THE WATER FLOW
The water output can be custom selected based on the desired flow. By simply rotating the
adjustable 3-way flow control knob you can select one of 3 output settings as well as
adjust the flow rate."

Click to expand...

They do but even if I have it on the, lowest setting which is the middle spray bar, it still kicks out quite a bit of force

Carlovel1 said:

IIRC Fluval U series have a little screw above the water outlet and if you turn it, the flow rate is decreased.
Carl

Click to expand...

It does but this is only if you have the top venturi jet working which, even with the screw full closed, is still more powerful than the middle spray bar.

JMcQueen said:

Aqua Tom said:

acording to the manual, the flow rate can be adjusted.


"ADJUSTING THE WATER FLOW
The water output can be custom selected based on the desired flow. By simply rotating the
adjustable 3-way flow control knob you can select one of 3 output settings as well as
adjust the flow rate."

Click to expand...

They do but even if I have it on the, lowest setting which is the middle spray bar, it still kicks out quite a bit of force

Carlovel1 said:

IIRC Fluval U series have a little screw above the water outlet and if you turn it, the flow rate is decreased.
Carl

Click to expand...

It does but this is only if you have the top venturi jet working which, even with the screw full closed, is still more powerful than the middle spray bar.

Click to expand...

Have it on the middle setting then direct the flow against the side if the tank. If it is still to powerful maybe its time to get a weaker one.