# How effective is CO2 Mist? Your Experience.



## John N. (Dec 11, 2005)

For the past couple of months, some folks have gone from using external reactors to diffuse their CO2 gas, and now are experimenting using glass diffusers, sweetwater airstones, powerheads, and other air misting devices to inject their CO2 via blowing bubbles around to the tank and into the plant beds.

How effective has it been for you? 
Please include your method, and your personal results.

-John N.


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## Bert H (Mar 2, 2004)

I may be in the minority here, but, for me, under my conditions in a ten gallon tank, it wasn't worth the hassle. I tried it for 3 weeks.

Tank: established 10 gal, pressurized CO2, 36W ahs light kit. 

Previously had been injecting the CO2 directly into the uptake of the AC mini which is what I use for filter. When I switched to the Azoo, found my CO2 levels were not changed, as measured via pH. Didn't notice any noticeable differences in plants and/or algae (had no algae issues to begin with). But I didn't like the idea of having to see an extra piece of equipment inside the tank and knowing I would have to be periodically cleaning the diffuser - didn't want any more maintenance issues.

But, as I stated originally, I think I am in the minority here.


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## Gumby (Aug 1, 2005)

On my 125, it seems like I had much better results doing the mist method. 

A about 3 months ago I hooked up a magdrive 350gph pump connected to an AM1000 reactor. Since then, it seems like I've had less gas in solution. 

I'm using a sump on my tank (previous piranha set up). I am very seriously considering ditching the reactor and going back to letting the CO2 bubble into the return pump. If I do I'll let ya know how it goes. 

One strange thing I've noticed is that some CO2 escapes the reactor as micro bubbles. In the high flow areas (areas where these CO2 micro bubbles are), the plants pearl a LOT more.


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## plantbrain (Jan 23, 2004)

Every tank has done dramatically better.

If you have a larger tank, using a spray bar + powerhead works extremely well and gives even distribution of the mist along the rear wall lower down out of view.

Not all set ups need this, and it can look bad in open designs, but then you can mix the mist well and have it reach most points in the tank.

You should see some pearling under high light in 1-2 hours, lots and lot that last few hours.

You should be able to look at the tank and see most all plants pearling 1-2 hours before the lights go out.

It's mainly a question of good current and flow patterns.
Even f you less/more gas, that is nt an issue, the results are.

Regards, 
Tom Barr


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## niko (Jan 28, 2004)

My experience with a "misting" CO2 supply is that the plants pearl very heavily. I have mentioned that before - the plants get covered with a gazillion microbubbles - both CO2 and O2 I believe. But since I fertilize extremely lean my plants don't grow ultra fast.

So once again - the good plant development and growth depends on many factors.

--Nikolay


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## HeyPK (Jan 23, 2004)

The smaller the CO2 bubbles, the greater will be their surface area in relation to their volume, and the more thoroughly the CO2 will dissolve in the water. The obvious way to compare the methods is to measure the CO2 concentration in the water and compare it with the rate at which it is introduced. It is the latter that will be difficult to measure. However, CO2 is pretty cheap, and there is no need to be obsessive in getting the most efficient method of getting it dissolved.


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## Gumby (Aug 1, 2005)

HeyPK said:


> The smaller the CO2 bubbles, the greater will be their surface area in relation to their volume, and the more thoroughly the CO2 will dissolve in the water. The obvious way to compare the methods is to measure the CO2 concentration in the water and compare it with the rate at which it is introduced. It is the latter that will be difficult to measure. However, CO2 is pretty cheap, and there is no need to be obsessive in getting the most efficient method of getting it dissolved.


When you're refilling your 20lb tank every 1.5-2 months there's a need to be obsessive


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## houseofcards (Feb 16, 2005)

Gumby said:


> When you're refilling your 20lb tank every 1.5-2 months there's a need to be obsessive


Are you only using it only for your 125g. I run co2 heavy, but something doesn't make sense here.


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## hoppycalif (Apr 7, 2005)

I tried the CO2 mist method first just using an Eheim ceramic disc diffuser under the filter return spray bar. I got pretty good plant growth, some pearling, but not spectacular. A couple of weeks or so ago I switched to a powerhead with a tank length spray bar mounted at the back, low, and with the CO2 tube just stuck into the inlet grill of the powerhead. I also doubled my lighting to 110 watts over 29 gallons. Now I get pearling a couple of hours after lights and CO2 on, and by the end of the day all plants pearl heavily. All of my plants now grow rapidly. I'm very satisfied, partly because the little powerhead hides behind some plants, and the transparent spray bar kinda disappears, plus no diffuser disk to clean.


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## Gumby (Aug 1, 2005)

houseofcards said:


> Are you only using it only for your 125g. I run co2 heavy, but something doesn't make sense here.


Yeah, only on my 125. I think the major problem is extreme degassing from:
1. An over flow box
2. Filter pads
3. Bioballs
4. ~1200gph flow rate

There's just so much breakage of surface tension on the water that it's near impossible to keep the CO2 dissolved.


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## houseofcards (Feb 16, 2005)

Gumby,
I'm not gonna get into why that is, I assume you have your reasons for needing that much surface tension and 1200 gph, but at least it explains why your burning so much co2.



Mist method:
Yes, I've been using now for a few months and it's the best method I have used yet. I too get pearling on most of plants a few hours before lights out.
In fact the pearling is so heavy it looks like I just clipped a bunch of stems and it's bleeding out. I have vertical streams popping up all over the tank. Never got that before when I used direct intake method or other methods.
I have a 72gallon tank with the glass diffusor 3/4 way down on the left side glass with a spray bar directly overhead blowing from the left to right. 

Surprisingly I still get some BBA on my hardscape and am going to push co2 oup a notch to see if this stops it.


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## Bert H (Mar 2, 2004)

> A couple of weeks or so ago I switched to a powerhead with a tank length spray bar mounted at the back, low, and with the CO2 tube just stuck into the inlet grill of the powerhead. I also doubled my lighting to 110 watts over 29 gallons. Now I get pearling a couple of hours after lights and CO2 on, and by the end of the day all plants pearl heavily. All of my plants now grow rapidly.


Hoppy, how do you differentiate the effect of increased lighting vs the effect of the change with the powerhead, etc?


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## reiverix (Mar 24, 2005)

It's by far the best method I've tried. An Azoo diffuser sits directly under a small powerhead that blows the mist into the path of a canister outlet, slightly angled downwards. Results were instant.


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## MoonFish (Feb 12, 2006)

I'm misting up a storm right now but it is kinda distracting seeing all of the suspended bubbles in the water. It seems quite obnoxious but the fish don't seem to mind?


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## hoppycalif (Apr 7, 2005)

Bert H said:


> Hoppy, how do you differentiate the effect of increased lighting vs the effect of the change with the powerhead, etc?


I can't differentiate between the effects of the lighting and the CO2. But, I also wasn't trying to test either one, just to improve my aquarium. I had already tried CO2 mist using an Eheim diffuser under the filter return spray bar, and saw improvements right away in terms of faster growth and more pearling. So, I was already convinced that I wanted to go further with the CO2 mist. I noticed I wasn't getting much growth of my alternathera reinickii or my blyxa japonica, so I knew I needed more light. Now both are doing fine.


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## Left C (Jun 14, 2005)

For small tanks I like the Hagen ladder with a Rio 50 powerhead placed slightly above the ladder and a little to the left of center. I get great pearling this way. 

The 6-7 mm bubbles that come out of the CO2 line at the bottom of the ladder are dissolved down to 2-3mm when they come out of the top of the ladder. Instead of these 2-3mm bubbles going to the surface, the Rio 50 then catches them and spits out a very fine mist of tiny bubbles. Many of the tiny bubbles float around and are dissolved. There's still some that go to the surface though. I can't count them all but it's not many. Maybe 20% or so that make it to the surface; I'd say.

The little Rio is only rated at 67 gph max. It comes with an adjustable flow nozzle and duck bill diffusior. It doesn't suck up any critters. My Amano shrimp climb all over it and my Betta likes to lay on the ladder right underneath the Rio. His fins aren't sucked up. The Rio has a flat bottom with intake slots to keep most things out. 

This just flat works in a small tank. It's like a combination of misting and regular diffusion. I have mine placed on the side wall instead of the back wall. I've even used it with a pressurized system too in a small tank. The only problem is that it sticks out into the tank some but the small fish like to swim around in the flow. For around $12 for the ladder and $8 for the Rio; it's hard to beat.


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## John N. (Dec 11, 2005)

*My Experience*

I've been listening in on the discussion, and decided to experiment with three methods of CO2 diffusion methods using a glass diffuser in all methods, for a duration of week for each method in a 28 gallon

1) CO2 through the filter intake
2) CO2 mist through powerhead
3) CO2 mist through powerhead & filter intake

*1) CO2 through the filter intake Eheim 2213*
Placing the glass diffuser right underneath the intake. This method effectively raised my CO2 ppm levels to 40+ ppms in less than 3hours once turned on. Plants were pearling about 4-5 hours after lights were turned on. Plants grew well. It works. Every 2 hours or so, the Eheim will spit out a bunch of bubbles, telling me that all the CO2 isn't getting completely dissolved, and collecting in the intake.

*2) CO2 mist through powerhead*
Placing the glass diffuser 7-8 inches below a low flowing powerhead directed into the bed of plants. This method effectively raised my CO2 ppm levels to 40+ ppms in less than 3 hours once turned on. So same as above. The plants pearling dramatic increased, and growth of plants like riccia, Alternanthera reineckii, Limnophila aromatica, Pogostemon stellatus, and a couple of others took off, growing rapidly each day*. Only problem with this method, the CO2 mist in tandum with pearling created a massive bubble overload to the eyes. Worked better than placing it underneath the intake. _*sudden growth possibly due to the additional 1 more week for establishment of the plants than method 1. _

*3) CO2 mist through powerhead & filter intake*
So my happy medium for this was to direct half of the glass diffuser underneath the intake, and allow the remaining bubbles flow upwards to the powerhead. This created great pearling throughout the tank, similar to method 2, but didn't create a havoc of bubbles that threaten the eye. 

All in all, each method works tried and true. I'm gonna be sticking to method 3 for a while since the plants are growing fantastic. I felt like I was wasting more CO2 through the intake with the sudden blast of bubbles through the spray bar. So my experience with the mist method was a positive experience.

-John N.


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## raven_wilde (Nov 16, 2005)

Question for those of you using the powerhead/spraybar combo... what kind of powerhead are you using? And do you all know of a type that could be submerged maybe midway down the back of my tank? Say about 12 inches underwater...


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## John N. (Dec 11, 2005)

I use the Viaaqua's discussed here. They work well, and do the job nice and quietly. I don't attach them to a spraybar though.

I placed the powerhead half way down the tank so 12"

-John N.


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## plantbrain (Jan 23, 2004)

MoonFish said:


> I'm misting up a storm right now but it is kinda distracting seeing all of the suspended bubbles in the water. It seems quite obnoxious but the fish don't seem to mind?


This is true, too much of a good thing.
But now folks arwe askign is the pearling something they want really, lower the light, then you have less plant production(and less O2) and more wiggle room with your chosen method.

Regards, 
Tom Barr


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## plantbrain (Jan 23, 2004)

I've said and had several local club members and web folks rave after I turned thenm on to Via Aqua canister filters, without a doubt the best deal for a canister filter for the $ and the quality and they are extrremely quiet like an Ehiem, IMO, they are every bit as good and well made as an Ehiem.

Note, if you are having slower response times, this can be influenced by the tank's size/dimensions, flow currents and the plant biomass.

The spray bar along the back wall is the most direct effect as it'll blast the mist right into the plant beds and rise up through them, this also reduces the mist in the water column, something to ponder...........

The bar sits along the rear lower part and is generally obscured by plants in most aquascapes. 

The current is directed towards the front of the glass or slightly downward.
A powerhead can be placed in the rear corn and fed with either a direct 1/8" ID CO2 gas line or, a red sea Berlin wooden airstone(these are the smallest available limewood stones) to reduce the cavitation noise. The fine mist does not produce noise as it entrers to the powerhead's impell, whereas the larger 1/8" dia bubbles do.

If access is an issue etc to the powerhead, a bubble counter may help or an "L" bend to bring the powerhead up high enough to see and service easier.

Note: you can likely fit the RS Berlin lime wood stones DIRECTLY into 1/2 ID spray bar piping.

So you can use the canister filter in a post filtering fashion(no burping or CO2 gassing the bacteria) so as to reduce the coalescence of the micro bubbles and increase contact time on the plants rather than the water.

This method has helped many folks thus far.
But.......some might not like the bubbles so there are few things that can be done suggested to reduce them floating all over.

I like bubbles on plants, not in the water personally.

Regards, 
Tom Barr


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## JLudwig (Feb 16, 2004)

I'm undecided with this. I tried it for a month, I have the inline reactor back on for a couple reasons. First is the mist itself, I don't care for the micro-bubbles in the tank... its much more controlled when its just the plants doing it, makes for better photos. Secondly, its more visible equipment in the tank, which I don't like. I was using a limewood diffusor, the one marine depot sells for protein skimmer (Corallife I think)? It got covered in a film I had to scrape off every other week or so.

On the positive side, it did work just fine - no stunting issues, etc. A nice glass one ala Amano would look good in the tank, the limewood was just ugly. Would be good for smaller tanks with HOT power filters I would imagine. Also my reactor (Ghazanfar/Gomer style) isn't so cat friendly, and its a PITA to pull return lines out of tank for photos.

No real surge in growth... but...I just replaced my lights for the first time in two years. The tank seems at least twice as bright, and with logrithmitic sensory perception, its probablly cooking now. I may not have been anywhere near CO2 limited before, perhaps I'll try again in a few months...

Jeff


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## John N. (Dec 11, 2005)

I know there's quite a few people using a glass diffuser or some sort to create CO2 mist. How's it going for you?

-John N.


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## Cavan Allen (Jul 22, 2004)

I tried a diffusor for a while and saw no difference whatsoever. I also got tired of cleaning it. Back into the Eheim.


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## John N. (Dec 11, 2005)

*Internal Reactor*

Well, I've been using Power Vortex Reactor now to see the difference, if any in growth. Plants seem to "pearl" faster with the reactor verses the misting applications.

In fact, within an hour, the reactor seems to have reach a CO2 saturation point, where the CO2 bubbles begin to swirl inside the reactor. Whereas the hour prior, the CO2 would dissolve near instantly under the turbulence and get pushed out into the aquarium.

So to me, the plant growth I've received and observation of the CO2 saturation point seems to indicate that dissolving CO2 in a reactor may be better for plants at the same bubble rate.



I'm going to watch things further.

-John N.


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## mahamotorworks (Nov 7, 2006)

I have used the Powerhead mothod since I started DIY CO2. The Micro Bubbles really bothered me at first but now I dont see them unless I am looking for them to see if it is time to replace a DIY CO2 bottle. Growth is fast. I see my plants pearl. Even tho my CO2 is at 50+ppm the fish dont show any signs of stress. I like the Power Head way of diffusing.

MAHA


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## eklikewhoa (Jul 24, 2006)

filtration: eheim 2213 with eheim lily pipe instead of spraybar
tank: 30g long
co2: diffusion by glass diffuser

I have my output on my eheim on the left rear corner of the tank pointing towards the right front corner which is where I put the glass diffuser. I have massive pearling coming from my stems,ferns, fissiden, HM, HC, B.japonica and downoi within an hour of the lights/co2 coming on. 

the tiny bubbles get caught in the flow path and go sideways throughout the tank and with 2-3bps I get almost 90ppm of co2 which is where I kept it for awhile but now I have fish in the tank and with less than 1bps I get 20-30ppm of co2. If I go to 2bps or between 1 and 2 my fish are gasping at the surface and within an hour or so the drop checker turns almost clear with a dingy yellow tint.

I am getting amazing plant growth and really high ppm's of co2 dissolved into the water so I am happy with the set up.


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## bijoon (Nov 20, 2006)

Isnt the increased pearling just from the bubbles getting trapped under leaves?


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## eklikewhoa (Jul 24, 2006)

bubbles trapped under a leaf is different from co2 saturation, with pearling you see the o2 coming out of the leaves.


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## will5 (Oct 26, 2005)

*Hi*



John N. said:


> I've been listening in on the discussion, and decided to experiment with three methods of CO2 diffusion methods using a glass diffuser in all methods, for a duration of week for each method in a 28 gallon
> 
> 1) CO2 through the filter intake
> 2) CO2 mist through powerhead
> ...


Hi i am going to call this *4

Inserting a sweetwater air stone into the in take on my hang on back filter. I have just done this about 40 minutes ago so i will let you know how things go by the end of tomorrow or Wednesday morring as far as Co2 ppm.

I have been using Diy Co2 straight in to the intake of my hang on back filter for some time now and have had this idea in my head for a while now. Trust me i know the risk of having it there but i thought it was worth the risk. With the old setup i could see many many micro bubbles and would just make 30ppm. For some reason 30ppm of Co2 is just is not enough for this tank.

I will check the results of this by my drop checker.*


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## AaronT (Apr 26, 2004)

Personally, I think the bigger factor behind mist diffusion and people's success with it can be attributed to increased flow. Whenever I increase the flow in a tank it always does better. Even distribution of the CO2 is what it's all about, whether through reactors or glass diffusers, if it's not making its way around the tank it's not growing plants well.


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