# Piranha Flow - Are People Going Too Far?



## Guest (Mar 4, 2010)

I've recently noticed a lot of people are getting and giving advice on flow. It seems to be the new trend for equipment on here.

What throws me off is how much flow people are recommending. I've seen people recommend* 2xKoralia 4's, which equals 2400gph*! This was recommended in a *180g tank*. This tank would thus experience over *13 times turnover rate per hour*, not including filtration flow. To me, this kind of flow should be reserved for reef aquariums where the organisms live in places where waves crash and corals rely on heavy flow for nutrients.

What most people seem to forget is that in river systems, fish spend most of their time on the edges is slow moving eddies, or deep where obstacles such a large rocks or mounds greatly reduce flow.

How much flow do piranha's really need, how much of it is healthy, how can you create large dead spots, and in what ways can flow be utilized to serve several purposes are the main issues here.


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## Guest (Mar 4, 2010)

Here are some examples of natural piranha habitat:



























_Vienna Zoo_


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## CLUSTER ONE (Aug 2, 2006)

Mr. Lahey said:


> Here are some examples of natural piranha habitat:
> 
> 
> 
> ...


 An aquarium isn't the wild. Powerbeads arn't necessarily used to mimic natural currents. You need current for exercise, and mainly to keep debris suspended to be filtered or to oxygenate the water H4 arn't very powerful. I have one in my 125 and its a very dispersed flow thats not even very noticeable past a foot or so.

For a 180 reef, i would say you could easily have Hk4. I have a H1 in my 15g SOFTIES reed in addition to a 250gph return after head loss. if this tank was hard coral i could do alot more.

Piranhas also live with alot of other fish in the wild, but it doesn't mean it would work in an aquarium.


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## dmackey (Jan 26, 2010)

interesting topic. i just set up a 180 gal and was wondering the same. as of now i have a koralia 3 and a 2000gph return and a 650 gph pump , i nothiced they are very active , but again is it necessary ? great post !


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## Ba20 (Jan 29, 2003)

In my 125 i have

Velocity T4 - 1225 GPH
Koralia Evolution -1050 GPH

Water Movement = Good "2 Cents"


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## Ægir (Jan 21, 2006)

If you take a river thats 100 miles or more wide at some points, even if its only flowing in "feet per day" that is still more GPH per 2'wide and 2' deep section than any of us have in our tanks. And not all areas of the Amazon are slow flowing like the pics, more of the wide areas are, but when the river narrows velocity picks up. Another thing you have to think of, is rivers flow ONE way basically, where as flow in your tank is "circular"

The main reason for high turnover isnt to "replicate natural environment" so much as it is to keep waste suspended in the water column until it can be broken down. The only reason to not push turnover rates through the filtration, would be the point water is flowing too fast for things to completely break down. In the river, waste only has to fall to the bottom... in our aquariums it has to go out the top into a filter.

As for your comment on SW aquariums... its not to provide nutrients so much, as once again to keep waste suspended and O2 levels up. I had on average 9000 gph flow in my sw tank... thats 58+ times turnover and i feel it was not near enough...

Its all preference really... i feel 10X turnover though the sump (or filtration) is a good number, its not to fast for the media to loose efficiency, and it keeps water from getting stagnant and building up toxins more quickly. In a SW setup, you would want that number to match the flow of your skimmer (or nearly) so it can keep up.

Bottom line, you cant put a specific number on it... its all what the owner wants... if you want a dark, nasty, swamp then dont have any turnover. If you want 1000000 GPH, and a fast flowing tank thats up to you.

I will comment, that i have a project in the works when i get some extra money... It will be a 8' "Linear Flow" tank, where water flows from left to right, and a closed loop pump (variable frequency drive) will move water from one end, to the other, and i can turn a dial and increase that flow up to 20,000gph (approx) or down to 10gph... Basically a section of river that flows as fast or slow as i want.


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## Ba20 (Jan 29, 2003)

Well said Egir


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## FEEFA (Nov 19, 2007)

I have 1100+ gph in my 220gal and thats just filtration.
How many times turnover is that?


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## Winkyee (Feb 17, 2003)

I have one old powerhead in my 180 with a large canister filter.
There's decent flow in areas and little in others and it seems to be working well for me. I'd hate to see a tank with water swirling like the Niagara river in springtime.


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## Guest (Mar 5, 2010)

Ægir said:


> I have 1100+ gph in my 220gal and thats just filtration.
> How many times turnover is that?


1110gph of flow / 220g volume gives you about 4-5x turnover, and is pretty good I would say.


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## Soul Assassin (Nov 21, 2006)

According to the calculator on this sight my 65 gal tall only needs 200-300 GPH, I got a 400GPH HK1, I agree with whoever said that its not that powerful, I could only feel the current for about a foot but I think it s good like that, your P wont be happy in a washing machine

4-5 times is sufficient to keep sh*t suspened until the filter does its job


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## CLUSTER ONE (Aug 2, 2006)

Soul Assassin said:


> According to the calculator on this sight my 65 gal tall only needs 200-300 GPH, I got a 400GPH HK1, I agree with whoever said that its not that powerful,
> its job


I said that. Like I said already i have a k1 on my 15g reef. Its decent current for a fw tank, but the salt water fish can easily swim in it despite the initial shock factor of 400gph


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## Guest (Mar 6, 2010)

My last reef had 40x turnover but I would never wish that upon a prianha!


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## bigshawn (Dec 29, 2005)

I haven't read anything where someone said they HAD to have current people as for advise on what others have on there tanks thats there preference not a rule, I agree there is a time where one may have to much current in there size tank


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## assclown (Dec 12, 2005)

here is where experience comes into play.........

is your fish comfy with a powerhead?

you have to add a powerhead and see if the fish likes it, if it swims away from
the currant than no it doesnt like it. i have 2 rhoms and the smaller one who is
in a 180g tank has a catallina 3300 in it real close to the top water line and its
doing close to 1000gph, he loves it...he will swim in the currant etc. and i have 
plenty of places he can rest.

my bigger rhom has a 2200 in a 240g, it does 850gph it didnt like the 3300gph
because it was struggling to swim and did not go into the currant.

so my point is this, rules are ment to be broken, see what your fish like and 
dislike and go from there


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## TheWayThingsR (Jan 4, 2007)

I personally have just a bit over 1000 gph for my 125, which is 8x. Keeps my water crystal clear.


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## ...Jay... (Nov 2, 2006)

this is a perfect topic for me right now. I'm setting up a tank and cant decide what to filter it with.

I can tell you that my old Ps went from minnows to full of eggs in 1 year. I had 2 little crappy filters rated for 10 gallon tanks on the back of a 55 gallon with 4 Ps in it. then after 6 months or so upgraded to a filter rated for like 30-60 gallons. Not turning over much water at all. I had to gravel vac twice a week at least, but thats what I did, so they stayed healthy. They only died because they turned black, paired off, and made beds. So I didn't want to bother them and stopped gravel vacing for about 2 weeks. After they died(because of my stupidity) I cut the suspected females open, and sure enough, full of eggs. I think if you have egg production in a year from babies, they are happy. And there was basically NO flow in that tank.


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## Ægir (Jan 21, 2006)

...Jay... said:


> this is a perfect topic for me right now. I'm setting up a tank and cant decide what to filter it with.
> 
> I can tell you that my old Ps went from minnows to full of eggs in 1 year. I had 2 little crappy filters rated for 10 gallon tanks on the back of a 55 gallon with 4 Ps in it. then after 6 months or so upgraded to a filter rated for like 30-60 gallons. Not turning over much water at all. I had to gravel vac twice a week at least, but thats what I did, so they stayed healthy. They only died because they turned black, paired off, and made beds. So I didn't want to bother them and stopped gravel vacing for about 2 weeks. After they died(because of my stupidity) I cut the suspected females open, and sure enough, full of eggs. I think if you have egg production in a year from babies, they are happy. And there was basically NO flow in that tank.


Water quality, and water flow are two different things... If you would have had more filtration flow, they prob wouldnt have died and that ridiculous gravel vac schedule would have not been mandatory. Even if you would have had almost no flow, and an excessive amount of media.


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## ...Jay... (Nov 2, 2006)

^ oh for sure. I know that wasn't close to enough filtration which is why I vaced so much. And that filtration isn't what we're talking about here. I'm just saying that there was no power head or anything, so the little filtration was all the water movement there was. And they felt comfortable enough to pair off at minimum breeding age. The crazy water I was changing probably helped with that though, so who knows?


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## Guest (Mar 16, 2010)

Not really a lot of agreement here, if I had to make a general statement I would say that most of us think 1-5x tank volume/hour is appropriate.


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## Ægir (Jan 21, 2006)

...Jay... said:


> ^ oh for sure. I know that wasn't close to enough filtration which is why I vaced so much. *And that filtration isn't what we're talking about here. * I'm just saying that there was no power head or anything, so the little filtration was all the water movement there was. And they felt comfortable enough to pair off at minimum breeding age. The crazy water I was changing probably helped with that though, so who knows?


Actually, your filter flow, is still "turnover" and the GPH should be added to your "total"

If you have 10 HOB filters, and no powerheads... you still have flow in your tank...

I always aim for 10x filtration turnover, (550gph on a 55 gal tank isnt much... ) and MORE in tank to keep waste suspended and allow it to get sucked into the filter, not settle on the bottom and decay.

With a saltwater tank... its a different story.


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## CuzIsaidSo (Oct 13, 2009)

I have a 46gal bowfront tank 36" long with a solo spilo in it. I'm looking into a koralia nano 426gph almost 10x do you think it'll be good enough?


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## Guest (Mar 17, 2010)

Yes that will be enough.


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## assclown (Dec 12, 2005)

all depends if your individual fish likes it............


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