# how much surface agitation do i really need / want?!



## 180g (May 20, 2014)

Im not going to have any on my 180 but Im going to have co2


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## AquaAurora (Jul 10, 2013)

I adjust my surface agitation in each tank (2 have bettas so have to keep more gentle) but generally just get enough movement to prevent bio film build up on the surface (oil slick look). If you have fish from high oxygenated water/strong current areas (many pleco breeds are) jack it up as much as you can without agitating substrate, blowing away fish, or blowing plants loose.
In general I set up the filter and kneel down to look at the surface from 'under water' perspective and look for a tiny bit of water movement opposite the filter (if multiples used, just watch for dead spots, a piece of plant debris floating on top helps show flow).


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## Steve002 (Feb 7, 2014)

If you aren't running CO2 then have as much as you like, and at least as much as you need to eliminate the surface scum. When your lights are on and the plants are taking in CO2 then since your only source of it is from the air, surface agitation is a good thing.


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## philipraposo1982 (Mar 6, 2014)

ty steve


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## denske (Feb 20, 2013)

How do you plan on the fish breathing? You need some movement for oxygen exchange, especially when using co2.



180g said:


> Im not going to have any on my 180 but Im going to have co2


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## Aqua Jon (May 28, 2013)

I wanted to add to this conversation. Hopefully someone can correct my thinking if it is wrong.

I had been told in the past that surface agitation reduces CO2 water column levels by allowing it to escape and is therefore undesirable in a planted tank? I don't believe that to be true, however it would be nice to have some validation on my thoughts.

Also, how do floating plants or tall plants come into play with circulation - do the massive roots block adequate flow and decrease agitation too much?


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## 180g (May 20, 2014)

denske said:


> How do you plan on the fish breathing? You need some movement for oxygen exchange, especially when using co2.


did you know that plants produce o2,,,, amazing right! :hihi:


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## Hoppy (Dec 24, 2005)

With DIY CO2 you could have too much surface ripple, since you can't increase the CO2 bubble rate, the amount of CO2 in the water will decrease. With pressurized CO2, you can always increase the bubble rate to compensate for the loss of CO2 from having lots of surface ripple. Surface ripple increases the surface area of the water, so it increases the amount of O2 dissolved into the water from the air. Having more O2 dissolved in the water is always good for the fish, since it makes it easier for them to live with the CO2 in the water. Growing plants do supply some O2, but most of it in the water comes from the air-water interface.


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## JoraaÑ (Jun 29, 2009)

https://www.youtube.com/watch?v=6fep-_8m8Ls


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## lauraleellbp (Feb 3, 2008)

Aqua Jon said:


> I wanted to add to this conversation. Hopefully someone can correct my thinking if it is wrong.
> 
> I had been told in the past that surface agitation reduces CO2 water column levels by allowing it to escape and is therefore undesirable in a planted tank? I don't believe that to be true, however it would be nice to have some validation on my thoughts.
> 
> Also, how do floating plants or tall plants come into play with circulation - do the massive roots block adequate flow and decrease agitation too much?


Surface agitation only results in CO2 loss on tanks where CO2 is being injected. CO2 outgassing is a non-issue on tanks that are not injected.



180g said:


> did you know that plants produce o2,,,, amazing right! :hihi:


Only during the day. Plants absorb O2 and release CO2 at night/in the absence of light.

This can be a major issue for people running high levels of CO2 with pressurized tanks. Tons of threads on here with people waking up in the morning with a tank full of dead CO2-poisoned fish. It's why I personally always recommend people with pressurized CO2 setups running an airstone on a timer set to come on when the lights go off.


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## 180g (May 20, 2014)

Hoppy said:


> With DIY CO2 you could have too much surface ripple, since you can't increase the CO2 bubble rate, the amount of CO2 in the water will decrease. With pressurized CO2, you can always increase the bubble rate to compensate for the loss of CO2 from having lots of surface ripple. Surface ripple increases the surface area of the water, so it increases the amount of O2 dissolved into the water from the air. Having more O2 dissolved in the water is always good for the fish, since it makes it easier for them to live with the CO2 in the water. Growing plants do supply some O2, but most of it in the water comes from the air-water interface.


im a very lowly status for planted tanks so forgive me if im wrong but cant you add more yeast and more sugar to a larger container (maby a 3 liter soda bottle) to compensate for the co2 loss? I know this wouldn't be as precise as pressurized but I guise it helps right?


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## denske (Feb 20, 2013)

180g said:


> did you know that plants produce o2,,,, amazing right! :hihi:



Let us know how that works out for ya, all wise one.


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## bucntears (May 31, 2014)

New to fresh water setup. Don't you have to have an air stone in the tank or is using a canister filter along with power heads enough to supply the tank?


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## Steve002 (Feb 7, 2014)

I notice a big difference in my fish's activity level between the CO2 being on and the air stone coming on after it.


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## lauraleellbp (Feb 3, 2008)

bucntears said:


> New to fresh water setup. Don't you have to have an air stone in the tank or is using a canister filter along with power heads enough to supply the tank?


*Most* of the time, airstones are optional on any freshwater tank as long as the tank is well filtered. If you're not injecting CO2, O2 supply should not be an issue.

If you're injecting pressurized CO2 at high levels, people may need to take measures to increase O2 availabilty to help their livestock offset the effects of the CO2.

So the answer depends on how you're planning on setting up your tank.


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## Aqua Jon (May 28, 2013)

thanks for answering a few of my questions! I'm still curious about floating plants disrupting the O2 exchange. From my own observations I believe that it does negatively impact the O2 production. Especially when all or most of the tanks surface has a dense growth of say, water lettuce or frogbit. There is surface protein in my tanks with floating plants. But I know there are some other missing factors. I imagine the roots also contribute to stagnation.


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## lauraleellbp (Feb 3, 2008)

On an unfiltered tank, maybe. Most tanks have really good surface area to tank depth ratios that even just a little water movement will provide enough O2 for an appropriately stocked tank. It's really only when we start making major changes like overstocking or adding CO2 that O2 levels might become a problem.

Or perhaps when keeping specialized high flow coldwater riverine species that by nature have high O2 reqirements.


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