# Too much flow???



## xxbenjamminxx (Aug 8, 2011)

WARNING - Possible dumb question ahead!

I was wondering if there could be too much flow in a planted tank? Im not talking about tearing all the plants up strong, but alot. 

Specifically, lets say a 75g tank with an AC 110 HOB, Eheim Pro3 2075, a Koralia 850gph, and a Maxi-Jet 1200. 

AC110 is rated at 500gph
Koralia - 850gph
Eheim - 330gph
Maxi-Jet - 295gph
totaling - 1875gph 

All the plants are "swaying", fish dont seem to mind, and it isnt blowing the sand substrate around at all, but just want to make sure that too much wont hurt the plants any.


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## Patriot (Dec 22, 2010)

The plants won't care unless it removes a lot of CO2 through surface agitation. The fish could get tired of swimming against the current.


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## xxbenjamminxx (Aug 8, 2011)

There isnt much surface agitation at all except from the HOB, since most of the current is slightly pointed down. I just popped in the Maxi Jet tonight for the heck of it and it got me thinking about this. Will leave it for a day or two and see what happens. Drop checker is still greenish yellow so unless that changes or the fish seem stressed I might just leave it, especially since I will be fill the back of the tank with corkscrew vals one of these days if they ever decide to make an appearance at my house and figured they will block alot of that flow.


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## Patriot (Dec 22, 2010)

the vals for sure will slow down the flow, I notice this after I clipped them and now the water level drops twice as fast.


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## Craigthor (Sep 9, 2007)

I run tons of flow in mt 150 and like it.

Craig


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## KH2PO4 (Jul 18, 2009)

Too much will definitely hurt. But it's more about current/velocity 
management, not the total flow in your tank.

Your total flow is 25x per hour. Let's assume all your pumps/filters perform
up to spec and your 75 g tank is 120 cm long.

25x is just 25x120cm = 3000 cm or 30 meters per hour. Most slow moving 
rivers still have more flow (turnover rate) than that.

But that being said, do you need all of them? 25x !


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## astrosag (Sep 3, 2010)

More flow isn't a problem for plants. It can be for fish, however. Depending on the species of fish you have, some are more accustomed to it and others not - this could stress the one that aren't. 

Like posters above me said, flow isn't as important as directing that flow to avoid dead spots - really, having flow's main purpose is to distribute ferts and CO2. For low tech tanks that don't have CO2 and water-column ferts, flow isn't necessary at all (aside from a little water agitation, perhaps).

Though you probably have zero dead spots simply because you overkilled the flow, just make sure the fish don't seem stressed and you'll be fine.

GL!


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## zdnet (Aug 13, 2010)

xxbenjamminxx said:


> I was wondering if there could be too much flow in a planted tank?


As mentioned in "Ecology of the Planted Aquarium", too much flow induce mechanical stress and reduce growth and photosynthesis. The recommended flow rate is 11 cm/sec.


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## Kathyy (Feb 22, 2010)

If I did the math right 11cm/sec comes out to 396 m/hour. If both KH2PO2 and I multiplied correctly we have nothing to worry about. I certainly don't have 25x flow in my tank!


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## zdnet (Aug 13, 2010)

Kathyy said:


> If I did the math right 11cm/sec comes out to 396 m/hour. If both KH2PO2 and I multiplied correctly we have nothing to worry about. I certainly don't have 25x flow in my tank!


Earlier, KH2PO4 wrote:

"Your total flow is 25x per hour. Let's assume all your pumps/filters perform up to spec and your 75 g tank is 120 cm long.

25x is just 25x120cm = 3000 cm or 30 meters per hour."

The above calculation converts tank volume (75 g) to tank length (120 cm). But shouldn't it include the tank width and height as well?


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## bpb (Mar 8, 2011)

If it is not bothering your fish already in place it is fine. Be careful adding new inhabitants though. I accidentally killed like 90% of my stock overnight by adding a strong powerhead to my tank. I went from 4x turnover to 11x turnover and, woke up to about 20 dead fish. They got exhausted swimming against the current and just gave up.


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## plantbrain (Dec 15, 2003)

I have 20-30x in most tanks, the fish love it.
Even the baby cardinals.........

1m/sec is fine for a nice current, low pressure, high flow is good, not high pressure.


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## ua hua (Oct 30, 2009)

bpb said:


> If it is not bothering your fish already in place it is fine. Be careful adding new inhabitants though. I accidentally killed like 90% of my stock overnight by adding a strong powerhead to my tank. I went from 4x turnover to 11x turnover and, woke up to about 20 dead fish. They got exhausted swimming against the current and just gave up.


I think that something else was the cause of your fish deaths. I highly doubt that a strong current would cause fish to die as many of the fish we keep come from rivers that have a stronger current than is in our tanks.


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## Daximus (Oct 19, 2011)

Depends on the fish you have more than anything in my opinion. My angels and discus run and hide every time they see power head, lol.


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