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Producing CO2 and other plant nutrients in the canister filter

2K views 19 replies 6 participants last post by  dpeco33 
#1 · (Edited by Moderator)
The idea is as follows: ordinary rice is primarily composed of large carbohydrates/sugar that are not soluble in water.When these carbohydrates are degraded by bacteria in the presence of non limiting levels of O2, H2O and CO2 is produced. Therefore, if I place a bag of the type used for filter media filled with rice in one of the compartments in my Eheim, CO2 should be produced and dissolved in the water? According to my primitive calculations, 100 grams of rice would correspond to approximately 150 grams of CO2. Just for fun I have put some rice in a container with water that I bubble w an airstone. The rice disappears over time but it seems to happen quite slowly.

Anyone out there that has tested this concept ?


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Should also mention that rice contains some proteins and other goodies so the rice bag would also lead to production of nitrate, release of phosphate, potassium etc.


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#2 ·
That's fascinating...

So I did a quick google search, it looks like this is a similar concept to yeast DIY CO2, but using rice as an alternative source of sugar.

Is it really that much CO2?
Is all that CO2 dissolved into the water, or is some of it lost?
Is the CO2 released slowly over time, or lots at once?
How does the price of rice compare to the price of CO2 over the long term?
Do you have a drop checker to see what the CO2 levels are at?

I'll be watching to see how it goes.

Brian
 
#3 ·
The difference between DIY and this concept is that here the CO2 is produced directly in the water column (canister filter). I believe that it is important to keep somewhere with a strong or extremely strong flow of oxygen rich water to ensure that it is metabolized completely. In the absence of high oxygen it would probably lead to formation of methane and other nasty things. Since it won't bubble like crazy, a strong flow over the rice would probably lead to complete uptake into the water.
Rice costs almost nothing so this could be an ultra cheap and ultra simple way of getting more CO2 to the plants. And since rice is a plant, it probably contains what plants need...


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#4 ·
The idea is as follows: ordinary rice is primarily composed of large carbohydrates/sugar that are not soluble in water.When these carbohydrates are degraded by bacteria in the presence of non limiting levels of O2, H2O and CO2 is produced. Therefore, if I place a bag of the type used for filter media filled with rice in one of the compartments in my Eheim, CO2 should be produced and dissolved in the water? According to my primitive calculations, 100 grams of rice would correspond to approximately 150 grams of CO2. Just for fun I have put some rice in a container with water that I bubble w an airstone. The rice disappears over time but it seems to happen quite slowly.

Anyone out there that has tested this concept ?
You mention that this process is best attempted in a high oxygen environment, so it seems this would be suitable as the final stage of a wet/dry filter. And since the addition of higher levels of oxygen (and the consequential reduction of CO2) in the water is the reason wet/dry sumps fell out of favor for a planted tank, logical application of this theory, if valid, should reintroduce the wet/dry sump as a preferred filtration system for a planted tank, right? By placing the rice "bed" as the final stage of the w/d filter, oxygen should be depleted and CO2 increased just before the water is returned to the aquarium. This is an interesting concept, but would the rice tend to break down into particulates and blow cloudy "rice water" into the aquarium or remain fairly solid as it broke down? How does it behave in your air stone experiment--does the water get cloudy? Did you dare taste it to see if it did, indeed, result in mostly water and (I'm assuming) off-gassed CO2? If the "rice water" scenario occurred, then another stage of fine filtration would be needed to capture and hold the rice particulates until they broke down into the desired components. Of course, a scenario without cloudy "rice water" would be ideal, but probably too much to hope for. My initial concern is components of rice other than basic H, C and O, but then white rice is a fairly bland and basic product, being pretty much just starch (and not much of the sugar you mentioned?), isn't it? Nutritionally, I believe it's extremely lacking in other vitamins?, minerals, or other beneficial food compounds, just starch. I could be mistaken about that, but I've always thought of it as? an almost non-nutritional "filler" used primarily to stretch the volume of more nutritional food items, only providing carbohydrates and little else. Of course, this aspect would be ideal for the purpose proposed, but I'm just not sure of the chemistry involved. I AM interested, though. Since it's something that can be easily produced as a DIY project, I'm very interested. I've always wanted a wet/dry sump filter and with my "new" large tank I was a little disappointed that it wasn't preferable for a planted tank, but now you have my hopes up! If I had more elaborate testing resources, I'd try it out myself (with a wet/dry filter), but at this point I'm still a low-tech planted tank novice without so much as a drop-checker!

Someone needs to get right on this before I have to go on and spend the money to replace my terminally leaky Fluval 305! Come on, "chop-chop"! LOL!

Olskule
 
#5 · (Edited by Moderator)
Have only done limited experiments so far using the quite expensive Uncle Bens brand. Anyway, what I have seen so far is that in the bubbling experiments in approx 1 pint of water and 1/10 tenth of that with rice I indeed observed some cloudiness but surprisingly little. When I added the same amount to a nano tank w only an airstone I could not see any cloudiness but here the relative water volume was much greater.
Wrt to overall nutrient content in rice I guess it is not perfect but a human can survive a long time on rice only.
I intend to test this in a larger tank w an eheim. But I think I will put the rice bag first to maximize O2 content and filter out possible cloudiness. I'm also considering starting with bio pellets that saltwater people are using. Apparently pure carbohydrates even though it is also produced from some plant. If it works, I guess one would see a drop in pH especially during the night.


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Have only done limited experiments so far using the quite expensive Uncle Bens brand. Anyway, what I have seen so far is that in the bubbling experiments in approx 1 pint of water and 1/10 tenth of that with rice I indeed observed some cloudiness but surprisingly little. When I added the same amount to a nano tank w only an airstone I could not see any cloudiness but here the relative water volume was much greater.
Wrt to overall nutrient content in rice I guess it is not perfect but a human can survive a long time on rice only.
I intend to test this in a larger tank w an eheim. But I think I will put the rice bag first to maximize O2 content and filter out possible cloudiness. I'm also considering starting with bio pellets that saltwater people are using. Apparently pure carbohydrates even though it is also produced from some plant. If it works, I guess one would see a drop in pH especially during the night.


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Just one more thing. Starch is a large sugar polymer.


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#8 ·
If final stage filtration was used to capture the cloud-causing carbs/starch before it clouds the tank, it would also provide another, but special bio-filter specifically? to break down the carbs/starch further, which would be the point of the whole thing, anyway.

But this all rests on the hypothesis that rice will be broken down to just water and CO2 in the first place.

Where did this concept originate--is it your original idea? My first guess would have been along the lines of the rice being fermented into an alcoholic "mash" instead, but then moonshiners weren't uncommon where I grew up, so my thinking might be skewed. :p

Olskule
 
#9 · (Edited by Moderator)
Have not read about it before I thought about it but I guess I'm not first. Seems pretty logical to me.
In fermentation it is apparently important not to add oxygen. Here it is the opposite: best would be a great surplus of oxygen to avoid production of ethanol and other nasty things . Although ethanol will also be de graded to H2O and CO2.

Starch that is becoming soluble would probably get trapped in the filter and degraded by bacteria.


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Perhaps I could also say it is an extension of the classical Walstad method. There one relies on fish food and fish to produce carbon dioxide and other nutrients. Here it is rice and bacteria.


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#10 · (Edited by Moderator)
It sounds almost too good to be true, but yet perfectly plausible. From what you've said, I would consider it an original idea since it is "an extension" of an existing method, but actually, I wouldn't even call it that, since the approach is entirely different from the Walstad Method, in that this process relies on more contrived circumstances rather than simply letting Nature take its course, as does the Walstad Method. Besides, almost all new ideas and inventions are simply "extensions?" of existing concepts or the combination of previously existing ideas or known principles, yet they are considered original, so don't sell yourself short. The screw is just an inclined plane (a ramp) wrapped around a cylinder, but when combined, they are so much more than either concept alone. Can you imagine where we WOULDN'T? be without the simple screw? Yet sometime, somewhere, someone put the two concepts? together and technology was born. I dare say that technology wouldn't exist without the "humble" screw, yet it was a stroke of genius the first time it was conceived.

If I had the equipment to better test water parameters (CO2, O2, etc.), I would test this out myself, but I don't. While I'm not interested in a high tech system at all (for some reason), this technique intrigues me, perhaps because of the more "natural" processes involved. Of course, I realize that it would be an artificially contrived situation, but the processes involved are entirely natural, so I wouldn't consider it an "artificial" introduction of CO2. If this pans out, you could be responsible for the next big thing in the planted tank hobby!

Do you have the equipment to test the various water parameters? There are many YouTube videos for making inexpensive wet/dry filters; my favorite uses a small, cheap set of plastic drawers sitting in a tank (or plastic tub) sump, and drilled to drip vertically into each drawer/media chamber. Do you plan to go further to test it out? I think it would be best tested by observing all water parameters (nitrogenous? values, CO2, O2, TDS) at each stage of filtration. Do you have the equipment to do that?

Olskule

(Sorry about all the question marks at the end of words; for some reason my phone seems to add them when I send the post. It's annoying.)
 
#17 ·
It seems to me that the opportunity to "fiddle around" with balancing technical aspects of an aquarium system is part of the lure of an expensive CO2 system, so I guess it's just a matter of choice. Personally, I like the "natural process" aspect of this idea as opposed to the more artificial means of a high tech CO2 system. Plus, it has the potential to be less expensive and more trouble-free to maintain once you establish a baseline for the proper amount and rate of decomposition for the rice, which, of course, will naturally require testing the first time the process is attempted, as would any new method.

Speaking of which, is there any progress toward testing this yet?

Olskule
 
#20 ·
I like the idea, a bunch.. how hard would messing around with a rice bag be every few months or whenever it is needed.. We all have to clean the filters periodically anyway.. would appear that the rate of co2 would be far more stable than the canisters would be as nature will only allow what it can..
Keeps the dreaded co2 poisoning from happening when a man made guage or diffuser or whatever else is in the system now used fails and gases all the inhabitants?
I think that if this works, would be ingenious.. If it works..
Good luck..I am following

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