# [Wet Thumb Forum]-Reducing or Difussing the Output stream from my Fluval 304



## TommyBoy (Jan 9, 2006)

Well, I set up my new tank yesterday (a 37 gal Oceanic Cube) with a Fluval 304 canister filter. Why this size canister: 1) intended fish occupants like "overfiltered" water; 2) the normal considerations for plants & CO2.

After turning on the filter I noticed my carefully set plants being blown by a stream of water from its output. This will be way too strong a flow for the intended occupants.

My question: 
1) Is there a way to safely reduce or diffuse the output from a Fluval 304 canister? 

1a) Perhaps a mechanical way, like a partially reduced intake by means of a plastic/saranwrap film over part of the input riser? Or EVEN inserting a ball valve in the intake tubing. 

1b) Can the impleller speed be adjusted?

2) Would buying a spray bar and setting it up near the substrate pointing back-at-the-glass and upwards help diffuse the flow? A friend has told me he uses filter floss/fiberfill to reduce the flow out of his spraybar. Would adding a spray bar and then doing that help diffuse the flow?

All tried suggestions greatly appreciated!

--TommyBoy


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## Steve Hampton (Feb 13, 2004)

Tommy, a few questions answered would help form a more specific suggestion.

1) Are you going to injected CO2 and if so are you considering an external inline reactor?

2) What media have you pack into your Fluval?

Understand also that the flow from the filter will be greatly reduce within a few weeks after the filter has ran and collected debris from the tank.


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## TommyBoy (Jan 9, 2006)

> 1) Are you going to injected CO2 and if so are you considering an external inline reactor?


No, I was not planning on it. I have been using DIY (yeast-based) in my smaller tanks with Hagen ladder/bubble counter. And, was going to start out using that with this tank.

I read Hawkeye's recommendation to not change the flow if you add an external reactor.



> 2) What media have you pack into your Fluval?


1 layer charcoal (as came with it), 1 layer peat, 1 layer ceramic cylinders (as came with it). I am a little concerned about the charcoal, and was considering something like bio-sorb or purigen instead.

-TommyBoy


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## Steve Hampton (Feb 13, 2004)

> No, I was not planning on it. I have been using DIY (yeast-based) in my smaller tanks with Hagen ladder/bubble counter. And, was going to start out using that with this tank.


That's fine, though it may take two ladders and two 2 liter soda bottles to achieve the desired results.

[QUOTE1 layer charcoal (as came with it), 1 layer peat, 1 layer ceramic cylinders (as came with it). I am a little concerned about the charcoal, and was considering something like bio-sorb or purigen instead.[/quote]

Why are you using peat? Also it doesn't look like you have any mechanical filtration other than the sponge filters...is that correct? If you do decide to eliminate the AC and go with Purigen, I'd recommend adding poly-fil and the sachet of Purigen together prior to the peat and have the ceramic rings last.


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## TommyBoy (Jan 9, 2006)

Taking these in reverse order...



> ...it doesn't look like you have any mechanical filtration other than the sponge filters...is that correct? If you do decide to eliminate the AC and go with Purigen, I'd recommend adding poly-fil and the sachet of Purigen together prior to the peat and have the ceramic rings last.


You are correct, I am currently relying on the "as is" sponges for my mechanical filtering.

Am I understanding you correctly that you would recommend getting rid of the AC (activated charcoal)? And, are you also recommending going to Poly-fil+Purigen sachets? If so, will/could that cause any kind of by-pass flow within (or through) the Fluval due to the density of the media sachet?

I've used a Bio-zorb sachet sandwiched between a sponge and a ceramic cylinders in an AquaClear before for fish that like their water "overfiltered" and that has worked great. From what I have been reading, you can re-cycle Purigen and it seems "polish" water (whatever that means...perhaps overfilter it?). But I am not sure if it makes any difference when you also peat filter.



> Why are you using peat?


I am going to be stocking this tank some fish that are listed as requiring 4.0 to 6.0 pH and without much deviation over time in water conditions. So peat filtration and "overfiltering" are also listed as recommended for them to attain "deep black water and clear water."


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## Steve Hampton (Feb 13, 2004)

> Am I understanding you correctly that you would recommend getting rid of the AC (activated charcoal)? And, are you also recommending going to Poly-fil+Purigen sachets?


Yes, add poly-fil to the first media basket, however it you are going to use peat forget about using AC and Purigen, just go with the poly-fil the help mechanically filter the water prior to your ceramic rings.



> If so, will/could that cause any kind of by-pass flow within (or through) the Fluval due to the density of the media sachet?


No much, you'll see that as the Fluval gets restricted such as when the poly-fil traps debris you will see a reduction in flow from the Fluval rather than by-pass occurring.

As a side note, if you were using Purigen, it's best to place the Purigen sachet after the poly-fil between the poly-fil and ceramic rings.



> I've used a Bio-zorb sachet sandwiched between a sponge and a ceramic cylinders in an AquaClear before for fish that like their water "overfiltered" and that has worked great. From what I have been reading, you can re-cycle Purigen and it seems "polish" water (whatever that means...perhaps overfilter it?). But I am not sure if it makes any difference when you also peat filter.


That works fine too, though heavy mechanical filtration with poly-fil provides the best results and allow the Purigen to chemically filter the water without having problems from it becoming a mechanical filter too.

Purigen will defeat to some degree the effect of peat, it will also lead to very early exhaustion. Basically they would be trying to achieve opposite results so you shouldn't use the two together.


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## TommyBoy (Jan 9, 2006)

THANK YOU!









I am really glad we've chatted. Thank you for taking the time to do so. Very informative too.

--TommyBoy


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## TommyBoy (Jan 9, 2006)

A "footnote" to my story?

Ever come across a story that taught you one lesson throughout it, and then ended with a punchline that negated the whole rest of the lesson/story? I am not sure if this is what's happening with this Fluval and its stream of water "issue" in my tank, but here's the latest development.

IAW some advice I got in another foum, I added a spraybar with drilled-out holes and everything seemed to be great before I went to bed [NOTE: I have NOT reduced the flow using the Aqua-Stop Bar.]. Yesterday I awoke to find most all my fish at the top of the water column. After the lights were on for an hour, they were still there so... I turned the holes towards the open waters of the tank, and added an air pump and stone blowing bubbles in to the stream of the spraybar flow. Then I headed off to work. Within an hour, I am told they all began swimming back in the lower layers.

I unlpugged the air pump last evening when I came home, and my fish returned to the surface (along with the shrimp, or at least they were noticed this time). As stated before, I am peat filtering and replaced the AC yesterday with bags of polyfil (IAW advice I got here). pH is still a bit higher (7.1) than I want it (5.5-6), but all other tested water parameters (Ammonia, Nitirites, Nitrates, KH, GH) are pristine/just where I think I want them. My tank is 24Lx18Wx20H inches. So for now I am leaving it bubbling. And, this morning everything seems A-OK. Everyone is still happy with the extra aereation.

Anyone else had to aereate their tank after reducing the surface disturbance?

Will this need to be a permanent addition?

If so, is does anyone have any preferences / anectoes / scientific data about air delivery (e.g., pros/cons, trade-offs, shapes/size of stones, placement with tank, etc.) into a planted tank?

How will this affect my trying to obtain a lower pH?

TIA,
--TommyBoy


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## imported_ashappar (Jan 21, 2005)

eliminating surface disturbance hasnt been a problem in my tanks. normally I would say I reach a saturation of oxygen during the day because of the plants bubbling. never have noticed the fish gasping at the surface in the am. if you need extra aeration then maybe something in your tank is consuming the oxygen...bacteria? too high fish load? only guesses.


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## Pop_Quiz (Nov 2, 2005)

New to the boards, but I had the same issue with wanting lower flows out of the Fluval 304 (it is on a smaller tank). I took the nozzle off the end and drilled a bunch of holes in it...instant diffusion but it still creates enough flow to keep things moving and you can always buy a new nozzle if you need more flow.


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## JERP (Feb 4, 2003)

You want to diffuse the output to reduce the current, not block the flow through the filter. You can use a spray bar or larger outlet nozzle. You might also consider splitting the outlet to each side of the tank. That way you have the same amount of water under filtration, but less current. 

Surface turbulance may solve your gasping fish problem. It will also prevent surface scum from forming. The turbulance shouldn't be any more than a ripple. It also looks cool.


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## ssuggaddaddy (Nov 18, 2005)

if im not mistaking.... i have a fluval 304..... and all yu have to do is lift the flow lever found between the intake and output on the canister.

i just lift that lever up to the desired flow.... 

simple.


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