CO2 Magic!

[The_Nexis_One]

I'll most likely be DIY'ing one out of a 2 liter and an air pump. If I can regulate the air down low enough that is... just going to have to play with it to see how low I can get it and what strength solution it would require.

John.

[graveyardworm]

The easiest way to regulate the air pressure down would probably be to use a valve setup with more than one valve. Regulate the pressure by allowing some to bleed off through another valve. Does that description make sense?

[The_Nexis_One]

Originally posted by graveyardworm
The easiest way to regulate the air pressure down would probably be to use a valve setup with more than one valve. Regulate the pressure by allowing some to bleed off through another valve. Does that description make sense?

completely.

I usually use a 2 gang air distro, but i'm concerned about getting reliable flow at that low of a release - thinking something like 6 bubbles an hour!... not sure I can regulate something that low with hobbiest air pumps.

we'll have to see.

Thanks for the reply (and sorry for the Hi-jack)
John.

[graveyardworm]

The hard part is going to be preventing pressure from building in the bottle.

[The_Nexis_One]

Originally posted by graveyardworm
The hard part is going to be preventing pressure from building in the bottle.

it will. but once the bottle expands (as much as plastic can) it should be 1 unit in, 1 unit out. I'm sure there will be some fluctuation from solution height change, but we'll see

John.

[charles matthews]

hello folks- I have a number of experimental refugia, and have been working with organic sources of carbon. I have done freshwater and outdoor freshwater culturing. I got interested in a confluence of observations regarding adding white bread to killifish outdoor cultures; and the "vodka" method.

Well, I have found that adding vodka, or white bread, or spaghetti, or oat flakes, to a refugium with a sand bed substantially increases the bacterial films, and can slow the growth of Chaetomorpha, where bacteriofilms will outcompete it for growth.

However, one very interesting observation to me was that very small pieces of white bread reliably produce a dense cloud of ciliated protozoa. And I was thinking of setting up a refugium without a sand bed, using just Chaetomorpha, and adding very small pieces of white bread in quantity sufficient to produce a stable pH through co2 production. The nice thing about this is that as the white bread is consumed, it will relsease the protozoa to the water column and be carried into the main tank.

I am interested in Dendros, but there are many other species that might benefit.

So- like freshwater tanks, has anyone tried dosing an organic source of carbon? Anyone interested in trying a small piece of white bread to see what grows on it?

[CELACANTHr]

Wow, that is pretty neat! I think I may have to try it! How will I know if it is giving og CO2? Will I just see bubbles? How big are "small" pieces?

[Samala]

Interesting.. but I dont think I follow. By the way, how do you keep the killies from eating the bread? My old killie cultures would have devoured any little bits of anything remotely edible in about two nanoseconds. Any links to more info on this idea?

>Sarah

[morphriz]

Very interesting thread this!!

I've just started experimenting with CO2 mist in my FW tanks but I thought I'd explain the general theory here since you're all on the subject.

Mist can be used as a way to dissolve CO2 in water. The microbubbles have very big contact area with the water, same theory as air in skimmers, so it's a very efficient way of dissolving CO2. However, the main purpose of mist is get microbubbles to attach themselfes to leafes. Aquatic plants can absorb CO2 directly from the bubbles instead of from dissolved CO2 in the water. If you have fish in the tank it's not a good idea, can even even unethical, to raise CO2 above 30ppm. With mist one can vent the water with a powerhead near the surface so that dissolved CO2 is at an equilibrium with air, i.e. 2-3 ppm, and have plants take up CO2 directly from the microbubbles. If you just mist with air the bubbles will have a CO2 content of at least several hundred ppm. If you mix in CO2.... well you get the picture. The pros of FW planted tankes havent agreed yet though on exactly how this works, even if it works at all. There are a few threads on the subject at www.aquaticplantcentral.com

Since my wife really dislikes the "rubble in water" phase of a reef I'm was planning to start a seagrass aquaria.. until I read this months RK.. then I was convinced

Well, that was my two cents...
cheers Mattias

[Samala]

Mattias, glad the article gave you some ideas! I am concerned about species selection across the pond in Sweden.. you may have access to more of the Mediterranean species that are subtropical and should do well in a tank. We had a member.. ozadars.. collect Cymodocea I believe and placed them in his tank last summer, but I didnt hear anything reported back on that tank since then. You may want to search for his post though. If you travel over to worldseagrass.org there is a lovely pdf file that shows the species diversity within the Med and other areas at the moment, would be a good starting point to see whats available to you.

That said, one of the distributors here in the states imported Halophila ovalis, so someone collected that out in the Pacific. If you have any contacts through wholesalers you might be able to get them to find seagrasses/macros for you to play with.

Keep the CO2 lore coming if you think of any good ideas/applications from your freshwater experience. I got out of freshwater planteds before misting was in vogue.

>Sarah

[Plantbrain]

Originally posted by Samala
John, I'm curious, what do they say? Are they open to the idea or do they think you're crazy, or.. ? Cause when I go in they dont argue with the girl who can grow 2 lbs of Caulerpa in a week from a 10 gallon. Not that thats a big feat, but they seem to think so when I bring it in for credit. I'm just curious as to how this is being received - both the concept of marine planteds as well as nutrient dosing in some cases - as an idea outside of this very small community here on RC.

>Sarah

No, it's quite common practice for phycologist to add things like 5% CO2 and nutrients to grow cultures.

It's the hobbyists that lack the understand in the horticulture and husbantry.

It depends on the goal, many hobbyists seem to have this notion all for one and one for all, like they are musketeers or something.......

Corals and fish etc are different, when you actually think about how a marine ecosystem is based, it all starts to make good sense.

The base of the food chain is algae. That is the interface between inorganic nutrients and the biological side, bacteria to some degree in a few cases in nature.

So it makes sense for all the drawn out banter to start at the base if you want to build an ecosystem.

Happy plants = happy fish.

There are some trade offs, many aquarist simply have a poor understanding of what those trade offs are and often only know and understand one method and often base all thier notions of why on correlation, not causation.

Then we get myths.

Then people think I am crazy.
But if you have nice tanks and excellent growth, bring in heaps O weeds all the time, maybe they crazy and you are the sane one?

Don't need a PhD to figure than one out.


Regards,
Tom Barr

http://reefcentral.com/agreement.php

[Plantbrain]

Originally posted by morphriz
Very interesting thread this!!

I've just started experimenting with CO2 mist in my FW tanks but I thought I'd explain the general theory here since you're all on the subject.

Mist can be used as a way to dissolve CO2 in water. The microbubbles have very big contact area with the water, same theory as air in skimmers, so it's a very efficient way of dissolving CO2. However, the main purpose of mist is get microbubbles to attach themselfes to leafes. Aquatic plants can absorb CO2 directly from the bubbles instead of from dissolved CO2 in the water. If you have fish in the tank it's not a good idea, can even even unethical, to raise CO2 above 30ppm. With mist one can vent the water with a powerhead near the surface so that dissolved CO2 is at an equilibrium with air, i.e. 2-3 ppm, and have plants take up CO2 directly from the microbubbles. If you just mist with air the bubbles will have a CO2 content of at least several hundred ppm. If you mix in CO2.... well you get the picture. The pros of FW planted tankes havent agreed yet though on exactly how this works, even if it works at all. There are a few threads on the subject at www.aquaticplantcentral.com

Since my wife really dislikes the "rubble in water" phase of a reef I'm was planning to start a seagrass aquaria.. until I read this months RK.. then I was convinced

Well, that was my two cents...
cheers Mattias

If you consider fick's 1st law of diffusive flux, you will see the idea behind this.

J= coeffficent * change in concentration/change in distance

J is the flux in/out

What is the coefficient of diffusion difference of liquid vs gases?
About 10,000time higher transfer flux

What is the concentrational difference?
1,000,000 to 30ppm? Say 90 % is lost from the CO2 bubble(pretty high level), you are still at 100,000ppm.
also, the gases evolving inward from the water will have the same diffusion rate issues as lost to the air above, roughly slowed 10,000 time slower, not a fast rapid process.
If it was, then the water would be in equilibrium with the air above, clearly that is not the case which is why we aerate, add CO2 etc.

Distance:
This is minimized because the bubble has enough bouyant and adhesive energy to rise up and stick to the weed's leaves/blades through that boundary layer that exist at the micro sclae at the leaf/blade surface.

They say I'm crazy and yada yada yada, but like I said, if I have dramatically better growth, higher O2 levels and this keeps going in each tank I set up with this, something is occuring.

Even if one of the three is correct, it's still way ahead of folk's thinking as to why this method works so well.

The limits on this are constrained by at least 2 factors: maximimal growth rates for a given ligth intensity(main issue) and surface area contact.

The surface area contact is greater with the dissolved CO2 vs the micro bubbles. This is fairly obvious.

So this likely provides considerable gains for the dissolved methods.

The main issue is how to tease apart what phase the CO2 is in when the plant/weed takes the CO2 up, it's is CO2[aq] or CO2[gas]?

You can label the CO2 with C14, but that will not tell you what phase it's in.

And in reality, how to do you figure out and isolate under submersed conditions 100% dissolved CO2 vs 100% mist micro bubbles?

The micro bubbles do dissolve and some fraction hits the plant/weeds surfaces.

So you get both CO2[aq] and CO2 [gas].

So an indirect method, and one that makes sense in measuring aquatic system production from primary producers and is the standard in Aquatic Bio, measure the difference in the methods using O2 levels.

Now this is interesting, you do not need to have the exact same CO2 [aq] dissolve level to show that mist works or not and improves the growth.

All you need is to have the mist treatment not to have more than the CO2[aq] treatment.

If the growth rate/O2 levels are higher, then you know that added O2 is from the mist, even if the ppm in solution is lower.

This makes your experimental set up much easier to maintain and control for variation.

But remember, they say I'm crazy but offer no solutions to the observations other than user variation errors in testing, lack of controls etc.

It's easy to be an arm chair aquarist and critique others without doing jack yourself.

But as Samala and (I said decades before with FW weeds), you keep bringing in the nice pretty weeds, even the very tough to grow ones, the proof is there.

There is a certain inherenet practically in this hobby, and in science.

If you don't try and are too scardy cat to try anytime, it is difficult to learn and grow. You take risk, make lots of mistakes and hopefully at the end of the day, week, month, years, you can make some sense out of things and have some understanding.


I think for marine tanks, the aeration method seems to do well, and on smaller experimental isolated tanks, CO2 is fine to play with. I'm a little leary yet and have not set up a good CO2 method for marine planted tanks but will in the coming months.

I have 2 research Caulpera taxifolia tanks here I tend to that are used to train the divers looking for the weed.

I have been neglecting things there but I have set them up this week with the skilter and mist the beejeezes out of the tanks.

I think I'll do some CO2 dosing as well and see what happens with the O2 and KH, pH.

Next I need some canaries to add to the "tank of death", shrimp tend to be good for environmenal stresses like high CO2/pH changes etc and the EPA has a few standard critters they use for LD 50's.

There is more concern about the impact of higher CO2 on the CaCO3 in the tank, it does dissolve fairly slowly in tanks, but you just never know till you try it and see how it effects a wide variety of critters.

Regards,
Tom Barr

http://reefcentral.com/agreement.php

[Samala]

Tom it is very good to see you around RC again. I would be interested to hear about the progress of using CO2 dosing, misting even, on the macroalgaes. The seagrasses really do seem to get a boost from it over aeration and the macroalgae in the tank do grow much faster.. but I'm not convinced yet.

It is likewise wonderful to hear you are friends with those at MBA, I was just SO impressed with the attention to plant and macro life when I visited. Really quite awestruck. I knew they were open system to the Bay, so I figured they were getting pretty good nutrient input there. The eelgrass tanks (both sunlit and artificial lit) were my absolute favorites.

At the moment I'm playing around with LC/LD 50 assays using Ilyanassa (y'know those horrible mud flat snails) larvae against chelated iron preparations, to see what readings really lead to trouble. I have stuck Palaemonetes vulgaris (grass shrimp) into highly loaded CO2 misted tanks before.. I cant measure ppm for CO2 though (can you think of a crafty way I'm ignoring?) but they were doing alright with 1bubble/second. The pH was about 7.2 with that. Not a pressurized system of course either, so again, an imperfect attempt, but thought I would relate that back. Grass shrimp are immensely hardy though.. so not the best assay animal for sensitivity.

I know you're a super busy guy but we (well, I) could sure use your insight a little more often here on RC, I'd certainly welcome your input.

>Sarah

[The_Nexis_One]

Originally posted by Samala
...
I know you're a super busy guy but we (well, I) could sure use your insight a little more often here on RC, I'd certainly welcome your input.

>Sarah

Likewise, I've always enjoyed your posts - please do keep the info flowing. Many of use are interested enough in Marine planted setups to try experimenting with our systems/investments to help further the understanding of fellow hobbiests (and ourselves). While I/our experimentation may be sub-par on many/most standards it is, never the less, base information from which to narrow the field of actual note worthy testing by someone with better resources.

Looking forward to reading more.

...now I'm off to get my print out so I can study what you posted until I understand it

Thank you,
John.

[Plantbrain]

A lot of what I post here and on the BarrReport is applicable to Salty plants as well.

There are some needed reservations, but many things can be applied.

MBa has some issues in long term horticulture of some plants, eel grasses is one.

Several eel grass restoration projects also have tried some poor ideas to transplant and grow grasses on rocks out in the Santa Barbara area and further north.

It might be several years before I get into the eel grasses, but they should do well with CO2.

Samala etc et al, I have a number of rough CO2 indicies.

One is a simple rough guess by lowering the pH by about 1 full unit will be equivalent to 25-30ppm of CO2.

Look here on the KH /PH.

Realize marine systems have other buffered systems than just KH, carbonate alkinity. You folks have a nice little borate buffer system influencing this and perhaps some hydroxide alk as well.

So indirect ticks can help.

See here for the table:

http://www.aquatic-plants.org/articl...hph_table.html

Say you have a KH of 10(or about 179ppm of alk) and a ph of 8.0.
You will have about 3ppm of CO2. Knock the pH down to 7.0 using only CO2 gas enrichment, now you have about 30ppm.

Try this for at a KH of 1 degree, then the at a pH of 7.0, you add CO2 to get 6.0 and now you have a CO2 of 30ppm, you asimply scale things up.

So if you have a multiple buffered system, the true KH' effect on pH at ambient will tough to measure, so allow a glass of tank water to sit for 24 hours, measure the pH.

Whatever it is, say 8.3, knock the pH down to 7.3 to get 300pm, or whatever range of CO2ppm you want.

Knocking the pH down to .6-.8 pH units will be fine also.

Note: add CO2 only during the light peroid when plants will use and need the CO2, this will minimize the high CO2 and dissolution of high CO2 levels vs a chronic high CO2 level.

Some shelled critters and perhaps some CaCO3 rich plants might not fair well at high levels of CO2.

Note, the salt content, TDS, salinity, KH etc all stay the same, only the CO2 and pH move, this is not the same as a pH decrease/increase with salts.

So do not assume that pH decline in and of it's self is bad.
It's unknown really in most marine tanks, I know it plays no role in FW tanks.

But with so many critters and weeds folks have yet to try, it's tougher to say.

I do not like to assume much about Marine tanks here, too many critters to test things out on.

We really have fewer genralizations that we can make at this point in time.

I do know you can get great growth using skimmers and such with the bubbles being added back again to grow macros well.
This is something we know to be safe.

I did not find a practical difference between CO2 and that method, but I have not looked into it, but will coming up here in the next two or three months.

I'm busy folks



Regards,
Tom Barr

http://reefcentral.com/agreement.php

[Fishfreak218]

updated pics?? please

[Samala]

Soon Fish.. soon. I will preface them by saying that there isnt too much change to the landscape of the tank.. mostly because of the sincere pruning efforts to keep it from being a single mat of seagrass. I have removed hundreds of plants in the last two weeks.

>Sarah

[orchidsnfish]

Well curiousity got the best of me. I made a stop at wal mart and got the stuff to build a DIY CO2 system for my planted 60 cube. The tank is empty except lots of cool macros and some snails so I figure now is the time to experiment on it. I've got my yeast and sugar water mixed up now. Just waiting for it to start producing CO2. I'm going to use the powerhead method for now. I'm very interested to see if I have the same results as Samala is having with the seagrass.

Angela

[orchidsnfish]

I have a question. Will the low pH from the CO2 hurt the macro? The pH was 7.2 this AM. Since the tank has nothing in it I'm not worried about killing anything besides the macro. If it will thrive with the pH this low then that's fine. I will definately be putting a bleed valve on it before anything else goes in.

Thanks
Angela

[Samala]

Holy cow that is low! I'm amazed you got it so low with just a coke bottle reactor. Whew. If you have calcerous macros (Udotea, Penicillus, Neomeris, some Acetabularia, Halimeda) I would be concerned for their survival. The rest of the macro should be okay to 7.8 pH (as low as I have gotten it in test tanks with powerhead turnover still going).

What's the rest of the water movement and filtration look like in this tank? Just curious to know if my little backup skimmer is helping to even out pH even more than I thought it was (for example, pH lower than say 8 or so just doesnt happen in that main display these days).

Keep me posted! I'm thrilled you took on the challenge.

>Sarah

[orchidsnfish]

Samala:
The pH didn't drop like that until I added a "chamber" to catch the CO2 to keep it in contact with the water longer. My chamber is a reptile bowl made of rock turned upside down. It blends into the rockwork and isnt really noticeable. Before that is was going straight to the surface and made no change in the pH at all. The powerhead I have it hooked into is really small and only moves maybe 200 gph so the CO2 goes right into my little upside down bowl. As for other filtration the tank has a CPR bak pac 2 and a big hot filter for circulation. There is not a lot of water movement as this will be a seahorse tank eventually when I get done playing with it.

Angela

[orchidsnfish]

The pH was actually 7.4 not 7.2. I took the upside down reptile bowl out to let more CO2 escape to the surface so well see what happens. Here's some pics of the tank. It's still pretty new. I ordered some cool macros from inlandaquatics that will be here friday. I also took some pics to keep up with the difference the CO2 makes.

Angela

[Fishfreak218]

WOW^^^ thats a NICE tank.. do ya think we could get som closer shots?

also Sarah.... UPDATE!!! please.. lol

[Samala]

Hmm.. here's an update, mwahahaha: One of my chestnut turban snails has sprouted up Acetabularia! The characteristic disc shape hasnt formed yet though.



>Sarah

[Fishfreak218]

LOL^ wat 'bout an FTS???