# how to determine how much surface agitation?



## Koenig44 (Aug 19, 2016)

I've got a 20g long, with a Seio 320 (320gph), and pressurized CO2, with a canister filter Marineland C-160. I see other tanks with more surface agitation than mine. How do I know if I have enough?


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## Quagulator (May 4, 2015)

I like having a constant but subtle ripple from my filter output alone the surface when the tank is completely full, the subtle ripple turns into a large ripple as water evaporates, but never any splashing. There is no unit of "surface" agitation, and each tank / owner will have a different opinion on how much agitation they would want. 

Biofilm on the surface, gasping fish and limited evaporation is a sign of too little flow. Having to use too much CO2, lots of evaporation and splashing is likely too much agitation.


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## Deanna (Feb 15, 2017)

I, too, maintain a very slight ripple during the day. I don't want to drive too much CO2 off during lighting hours. Then, when lights go off, I have a Hydor Koralia (similar to the Seio), sitting just below the surface, that ignites and creates strong rippling to help drive off the CO2 but, more importantly, to increase the O2.


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## AbbeysDad (Apr 13, 2016)

I often wonder why those that inject CO2 don't put a small air pump with an airstone on a timer to run at night?


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## mgeorges (Feb 1, 2017)

AbbeysDad said:


> I often wonder why those that inject CO2 don't put a small air pump with an airstone on a timer to run at night?


Some do, but it's unnecessary. If you're not gassing your fish at saturation during the day, they're going to be fine over night. And as long as you're running a constant flow of CO2 during lights on, your water can only become so saturated. Not like there's a risk of toxic buildup over time.


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## KrypleBerry (May 23, 2017)

I run my co2 24/7 and have decent ripple on the surface. Tbh, I havent found a point of surface agitation where I had to adjust my co2 at all and my tank lasts 10 months this way running 2 aquariums. One thing Ive seen in many tanks without proper gas exchange is cyanobacteria growth (GSA). I keep my spraybar pointed along the surface of my tank just to help with gas exchange, my filter also utilizes a surface skimmer. In column and cube tanks its especially important to have good surface agitation as they dont have ideal surface area to begin with and it increases drastically by doing so.


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## OVT (Nov 29, 2011)

mgeorges said:


> Some do, but it's unnecessary. If you're not gassing your fish at saturation during the day, they're going to be fine over night. And as long as you're running a constant flow of CO2 during lights on, your water can only become so saturated. Not like there's a risk of toxic buildup over time.


I don't think that is always true, and I learnt that the hard way.

Lights go off and the plants switch from consuming co2 and producing o2 to consuming o2 and producing co2.

At lights out, the residual co2 does not drop like a stone.

In a heavily planted tank, the perfect storm is when the co2 concentration at night goes above fish tolerance level.

The folks who minimize surface agitation during the day to save some co2 pay first.


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## mgeorges (Feb 1, 2017)

OVT said:


> I don't think that is always true, and I learnt that the hard way.
> 
> Lights go off and the plants switch from consuming co2 and producing o2 to consuming o2 and producing co2.
> 
> ...


This might be an issue if you have absolutely ZERO surface agitation. I've never experienced this, however, and like KrypleBerry, I too would run CO2 24/7 back when I first started with no ill effect. No real benefit either, but that's a different story. We inject high levels of CO2 into our tanks, what plants produce is rather negligible in comparison. If you have ANY surface agitation, you'll be off gassing CO2 and simultaneously introducing O2 into your system. My systems never fully off gas, but I'm not at any risk of going above a set saturation based on my injection rate. 

I have murdered a bunch of fish by crashing O2 levels at night with Prime. OD'd the Prime when doing a water change after lights off, came in to find half my fish dead and the other half motionless and gasping, never seen my drop checker so yellow. Air stone fixed that problem and saved everyone that wasn't already dead, but that's not a natural CO2 poisoning, obviously. Only time CO2 has ever been a problem for me though.


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## Jeff5614 (Dec 29, 2005)

I have a good amount of surface agitation day and night. The fish are more active and the water is clearer. It also allows me to maintain a stable CO2 level throughout the day which is harder to do with little surface movement. 

This is another topic like water changes and dual stage vs. single stage that can turn into an endless debate.


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## Surf (Jun 13, 2017)

> One thing Ive seen in many tanks without proper gas exchange is cyanobacteria growth (GSA)


I believe that is the case with Black Beard Algae.


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## madcrafted (Dec 23, 2017)

I allow as much surface agitation as I can without actually breaking the water surface, so the ripples are pretty aggressive in my tank. This way I don't have to bother with air stones and all that jazz. A simple pH check assures me that it's degassing at a fairly quick rate after lights out and I only did this during initial set up. I haven't fooled with it since. It's very easy to achieve 30 ppm+ by increasing the flow rate a tiny bit to counter gas exchange from such heavy agitation. Whatever CO2 is "wasted" by doing this is offset by the piece of mind that my fish and plants are all happy. As long as you aren't running to refill tanks often, why not just supply ample amounts of both CO2 and 02?


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## Greggz (May 19, 2008)

AbbeysDad said:


> I often wonder why those that inject CO2 don't put a small air pump with an airstone on a timer to run at night?


I do just that. 

When CO2 and main lights are off for the night, quite heavy aeration with air pump begins. I noticed some positive changes when I started with it some time ago. Actually saw Pikez on TBR was doing it, and that was good enough for me.

In general, a well oxygenated tank is a healthier tank. Not just for fish, but for plants and the entire eco system as well.

As for surface agitation, I like a constant ripple. CO2 is cheap. Keep the tank well oxygenated and your plants and fish will thank you.


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