# Serendipity? Low tech tank making 25-35 ppm's of CO2 by itself?



## lauraleellbp (Feb 3, 2008)

I'll be curious to see how long it lasts.

When did you do your last water change?


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## ukamikazu (Jun 4, 2010)

I haven't changed the water in almost 48 hours. All last week the tank sat completely empty until yesterday.

At this moment, the drop checker is still holding that same emerald green and the plants are still pearling. Still no bad odors. I've been staring at it in rapt fascination all this time.


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## jsuereth (Dec 21, 2010)

Wow, that's just amazing. I had read studies that decaying organics can produce enough CO2 to sustain plants, but this is just astounding. 

My wild guess would be all that O2 kicked your bacteria into high gear. It seems a bit crazy though.

Let us know what happens next. I'd love to know if this kind of a setup could be controlled


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## macclellan (Dec 22, 2006)

interesting. decaying organisms producing co2 is my guess, and will go away in a few days at most.


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## ukamikazu (Jun 4, 2010)

jsuereth said:


> Wow, that's just amazing. I had read studies that decaying organics can produce enough CO2 to sustain plants, but this is just astounding.
> 
> My wild guess would be all that O2 kicked your bacteria into high gear. It seems a bit crazy though.
> 
> Let us know what happens next. I'd love to know if this kind of a setup could be controlled


That is actually the territory I would like to explore one day. Do you know what a nitrate reactor is? Reefers use them sometimes and a company called AquariPure tries to market them to freshwater aquarists.

They are essentially tightly packed canister filters filled with media like Matrix except water flows very slowly through them. The point is to create anaerobic conditions and host a bacterial colony that converts nitrate into diatomic nitrogen gas. They are powered by either tossing in cheap booze like vodka or sugar, sucrose namely. The end result is nitrate is converted into N2 and the other products from the reaction are water and CO2. If you actually write out the chemical equation and balance it, a lot of CO2 is produced. The bacteria, like in live rock, can handle some exposure to oxygen because they are protected by another bacteria and they dig in deep into the media that hosts them. I wonder if I haven't accidentally made my canister filter into a nitrate reactor.

If I want to keep it going, that means leaving it alone and letting it get dirty. I could feed it with my fertilizers, but dosing alcohol or sugar seems foolish. I also don't know what other byproducts could be produced since it is not a completely clean reaction. I don't even know if it is fish safe right now, but the plants are taking it well. Different kingdoms of life, different requirements. Cidex (glutaraldehyde) is similar in composition to sucrose and alcohol so I wonder...

How would one even going about reproducing this kind of thing? It's all very fascinating.


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## ukamikazu (Jun 4, 2010)

macclellan said:


> interesting. decaying organisms producing co2 is my guess, and will go away in a few days at most.


But to sustain it? That would be very interesting. If it all goes away, I'm fine with that, but still, to not have to lug around and fill CO2 canisters and make just exactly enough as you need it? I almost want to try a purpose built nitrate reactor to see how far you could go with it.


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## macclellan (Dec 22, 2006)

it's not like nitrate reactors are easier or cheaper than injected co2. You have to replace the sulfurous-rich media as it's depleted (it's not like seachem matrix... it's more like GFO... a small granule that needs replaced). that's more expensive than injected co2, and needs replaced more often.

people typically dose vodka directly to their tanks to feed the anaerobic bacteria. google or go to RC and search "vodka dosing". this is an alternative to a nitrate reactor (though you could use both) not a part of a nitrate reactor... the idea is to feed the bacteria with a carbon source, which the vodka provides. Again, it is much simpler and cheaper for our purposes to inject co2 (because eliminating nitrate is not also a goal for planted tanks unlike reef tanks).


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## ukamikazu (Jun 4, 2010)

I'm aware of this, the idea is intriguing, you must admit.

Some of the DIY nitrate reactors don't require a sulfur supply so you don't have to worry about replacing the sulfur because there is none and thus no sulfuric acid to neutralize at the end of the process. Entirely biological. Feed your fish and plants, you help feed the reaction. 

And you're right, our nitrates are very precious to us.

I'll check in tomorrow and see if the CO2 has dissipated.


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## macclellan (Dec 22, 2006)

it would be neat though!


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## ukamikazu (Jun 4, 2010)

It's 07:00. The drop checker is still green. I'll check again when I get home.


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## Moloch (Jan 31, 2011)

Following along. I don't know enough to have an input on this but it's an interesting project.


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## Hoppy (Dec 24, 2005)

I can't see how anything organic could contribute that much CO2 to the water, and I can't see any inorganic substance that would do it. Are you sure your drop checker is working right? Using distilled water with baking soda in it to set the carbonate hardness at 4 dKH? Using non-out of date pH reagent? If this turns out to be natural CO2, for real, we need to find out what is doing it, then quickly patent it!

One test you could try is putting an airstone in the tank and running a good stream of bubbles, then watching for the drop checker to go more blue. Whatever the CO2 comes from it will still leave the tank quickly with any water agitation.


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## ukamikazu (Jun 4, 2010)

That's what I'm saying!

But to answer your questions, all my reagents and other related impedimenta are good and tested okay. 

I put in another drop checker before I left this morning. We'll see what has happened when I get home from work tonight. 

As interesting as the idea is, having enough decomposition to make sufficient amounts of CO2 means that I would also be hosting my own private cess pool. In the long run, that is not a good way for me to run my show.


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## ukamikazu (Jun 4, 2010)

Just got home, it is about 19:00, both drop checkers are lime green. Pearling is less pronounced probably because the oxygen from the peroxide treatment has finally equilibrated. I'll toss in a bubbler tonight after lights out. Waste not, want not after all...


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## ukamikazu (Jun 4, 2010)

Well, I don't have a large enough spare air pump to give me the churn I want so I just turned the spray to face directly upwards giving a nice gentle rapids effect. We'll give it a couple of hours and see.


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## ukamikazu (Jun 4, 2010)

It's about 07:10, the drop checkers are now a very dark green trying to become a very light blue. I've turned the spray bar facing back down again. When I get back home tonight, I expect the drop checkers either to be at the same color as they are now or light blue again.


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## ukamikazu (Jun 4, 2010)

19:45 and we are sitting at a lovely dark jade color. It seems to have partially built back up. Hmmm...


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## ukamikazu (Jun 4, 2010)

07:36 and we are back to emerald green.


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## ukamikazu (Jun 4, 2010)

Just settled in, it's 19:31 and we are back to pale blue. It was a fun ride while it lasted. I can't help but think I accelerated the process or skewed the experiments by adding two pounds of healthy plant material to the tank last night. 

I almost want to try this again. For grins, I've refreshed the drop checker solution and replaced it into the tank. I guess I'll have to get another CO2 rig. Oh well, them's the breaks!


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## lauraleellbp (Feb 3, 2008)

Really interesting observations!

I wonder how much was the death and decomp of your biofilter?


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## ukamikazu (Jun 4, 2010)

It had to be all of it. 16 ounces of peroxide was probably overkill, but I would say that is definitely what helped liberate the CO2, natural processes took care of anything that was left. The water is incredibly crystal clear right now. 

Food for thought.


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## Hoppy (Dec 24, 2005)

Well, we learn something new every week with this hobby!:icon_excl


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## ukamikazu (Jun 4, 2010)

Spoke too soon!

It is 07:16 and the drop checker is lime green. Lights go off at 23:00 and back on again at 11:00, so 12 hour photoperiod. If that's the case, it should be blue a couple of hours after lights on...

Okay, everyone back on the bus!


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## ukamikazu (Jun 4, 2010)

*Mystery Solved!...*

...or alternately entitled, "How to turn any canister filter into a stink bomb for fun and profit!"

Step 1, get a canister filter, preferably with loads of carrying capacity like an Eheim or a Rena.

Step 2, this is the most important part, pack it absolutely senseless with media, any media. Just enough until you lose at least half your rated flow.

Step 3, let simmer for months.

Step 4, the payoff! Start dosing with a ridiculously powerful reducer as your plants' carbon source because you're too much of a cheapskate to get proper pressurized CO2 even though you already have a box full of regulators, because, you know, a cylinder and the gas itself is just such a financial bind. 

Step 5, let the reducing environment and bacteria do their dirty work and Robert's your mother's brother, you have a biological nitrate reactor-cum-stinkbomb in your home! Good for you...

Well, the way I figured it out is because since I started posting this bizarre little diary was after the fact. Since I began the water was crystal clear and the plants happy. Then the mysterious CO2 went away so I just started dosing Cidex shortly thereafter until my GLA regulator arrives. Then, all the previous symptoms came back as of yesterday, but I caught just in time tonight! The cloudy water tipped me off immediately. 

Of all the interest I've taken in this, of all the emergency measures I forgot to do one, simple thing. Clean out the canister filter which I just did. The thing still reeked when I opened it like a Port-O-John in the middle of Summer in Death Valley! But only in the bottom most basket which was stuffed with very dense filter pads. The next two baskets were totally stuffed with Ehfisustrat Pro, so much so that it took along time to drain them after I removed them. So, I gave the filter pads a very rigorous wringing under tap water until they stopped running black with foul smelling sludge, rinsed the Ehfisubstrat and split it evenly between two filter baskets (this is a Rena FilStar Xp3 by the way), rinsed them good, returned the canister to service and I've got all my flow back, easily double what I had earlier. Hopefully tomorrow it will start clearing up but I'm going to do a big water change anyway just to celebrate.

Thank you for your attention.


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## kuni (May 7, 2010)

If there's a way to make Step 3 happen on a faster timescale, this method could be pretty cool...assuming a tightly sealed canister, of course!


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## ukamikazu (Jun 4, 2010)

This is not something I would suggest anyone do unless they are just incredibly curious or have advanced reef keeping experience.

Having said that, now, if you wanted to do it on purpose you will have to wait at minimum two months so the necessary anaerobic bacteria can establish themselves. 

If you really, really are curious about how to build a coiled nitrate reactor, have a look at this,http://saltaquarium.about.com/od/diydenitratorplans/ss/sbscoildenitrat.htm.


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## lauraleellbp (Feb 3, 2008)

Yeck!!!! :confused1:


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