For the sake of discovery I'll cut some limewood stones with a 3/8" plug cutter. Bore and install an air tube, and insinuate them inline and see what shakes loose ? Such an airstone would be use specific and require exotic (unconventional) process though. They could be placed in a simple union though, and replaced pretty quickly at will. WTH why not ? Prof M

This should be interesting! You will have the airstone located so the high velocity water flow can rip bubbles off the end? That would be a neat mechancal design problem.

In line. As far as which direction the bubbles flow from the stone that's a matter of whether you bore W/ or across the grain. Flip em upside down and they all look alike ! Fitting a stone within the venturi is like building a ship in a bottle, this coming from a man that's accustomed to working sub-scale.

It makes no difference to me "How" the results are acheived. Only that they are, in a practicle manner.

It is interesting though. Given your background, and experience you could roll up yer sleeves and dive into it ? Bench racing design and theory is the only way to push the envelope. As always your expertise is welcome, and appreciated. HTH. Prof M

Here's a simple solution to a micro misting stone:

Take a nice Tygon tubing, say the 3/16" OD stuff.
Take a small piece of the ceramic or the limewood material.
Cut/dremel, sand, carve etc into the cylinder shape about 3/16" dia x 1/2" L, wedge this into the tubing end.

Viola, a small diffuser stone.
About as small as you are going to get. Not much capcity, but that is the trade off for smaller venturis etc.

Red SEA make a tiny berlin skimmer wood stone, 1/2"Wx1/2"Dx 2"L

Now you can go further, but this is simple and folks have the stuff to DIY this.
Now, that venturi........you can use a larger constriction, thus not as much pressure head loss, and still achieve similar misting results.

The goal is to get tiny bubbles flinging out of the end of the filter tube in line.

The other idea is to use several of these micro bubblers in line.
You can also make tiny orifices out of glass and plastic tubing by melting them and pinching the tips way out, like when you pull cheese pizza apart.

I will say that the little ADA beetle knock offs from Aquaticmagic.com have really impressed me. I'm thinking the best method is to simply add the disc in there and turn the gas off at night etc and work with the mist there.

The cost is just hard to beat economically and the AM glass ware is dirt cheap and good.

Now when you strart dealing with 125-200 gallons and above, sumps etc, then the venturis come into play.

With a sump, a venturi is a very easy device that will not impact the flow rate of the filter since you can just add alarge powerhead into the sump and feed the outflow into the return side of the return pump.

Many add the gas to the return pump and leave it at that.

If you have extra power and have reduced the flow with a ball valve in a sump set up(A common thing), then adding a loop to fully exploit the remaining back up flow using a venturi ain't a bad idea either.

I think for those seeking to remove the items from a tank though, this is not a cost issue, more aesthetics, then the venturi is a very worthwhile thing.


Regards,
Tom Barr

Tom,

Are you talking about AM Spio series? Also, did you try any of their CO2 hardware such as splitters?

Regards.

Vladimir.

No, the Rhinox diffusers, they look like the beetle series from ADA.

The little tiny diffusers I did not like, they clogged easily and had consistancy issues with the several I used(6 of them).

Some may work, the ones I used did not and one was never able to produce any bubbles without high pressure, so high it would routinely blast off the CO2gas line no matter what I tried. I messed with them for about 6 months.
Got rid of them.



Regards,
Tom Barr

The booster pump is probably not the only way to go. There is a ton of information on protien skimmers, and I've been reading a lot. There are pumps that have special impellers that break up the bubbles. I don't know if you would get a bubble that is small enough. The smaller the bubble, the less surface area, and the more time it takes for the bubble to diffuse, and therefore can get Co2 moved all over the tank.


I've sent the following to Mazzei's engineering support for some help,

Please be sure to pass along the answer you get from Mazzei. I find it an interesting subject with DIY potential that could be even more fun.

If you intend to use the 287 then I'd suggest drafting the Co2 through the intake of an Ocean Runner 1700. This works like gangbusters !

If you intend to run off the output of your 2224 I'd suggest using 5/8" barb x 3/4 mpt reducers and the 784, but you will want to augment the gas port down to 1/16" > or less. Remember that the internal gas orifice is actually quite a bit smaller than the external barb. Depending on the model type of Venturi you are using Mazzei does carry stainless steel drop in ports for gas injection. HTH Prof M

ah.........there is it is.
Perhaps.

Let's think about this statement.

This could be key to the entire notice about mist/microbubbles/apherons and why those bubbles persist a logn time while the larger gas bubbles inside a reactor quickly diffuses into solution.

It terms of total gas volume per bubble, the surface area is smaller, but in terms of total surface area, 10,000 micro bubbles vs 1 large bubble?

It's say the micro bubbles have far more surface area given that the gas volume for the 10,000 and the one large one are the same.

Agreed?

Now think about surface tension. Which bubble has more? The apheron or ther large bubble?

Obivously the microbubble.
Which bubble would be more prone to coalesce due to this tension?
Which would be more sticky due to surface tension?

Some might say all this disscussion is for not, but given the importantce of CO2 in planted tanks that us gas CO2, it is a critical thing that can always use a new understanding.

I think the size issue is critical with this theory/method.

I always go back to the Fick's first law:

J = -D * d/dx[C/x]

J is the flux, generally thought of as moles per time/area or for us ppms per secs/surface area.

D is the diffusivity constant.
Note: this changes when the phase of the compound changes!!!
Liquids diffuses much slower than gases!!!
About 10,000 times slower.

We know that from CO2 not equilibrating with ther air above, it takes a long time(several hours or more), but in air? Takes a few seconds.

C= concentration, that is not black and white as some seem to imply.
The area immediately around a bubble will have higher CO2 ppms than the water further away.

X is the surface area...........now think about a larger bubble and think about a micro bubble here.

When you think about flux, think about it in terms of the plant, not the water so much.

Think about what differences the micro bubble would have on CO2 flux into the plant.

Okay? Keep thinking.

Now think about what rate and what other gases are in solutiont that might quickly and rapidly flux into the microbubble, remember O2 and N2 are very insoluble and do not dissolve well. These are the 2 main gases besides the
CO2 we add.

They also have to dissolve based on that slow transfer of gas to liquid and from liquid to gas, 10,000x slower..............not just CO2 out of the bubble.

Another effect the microbubbles might have: increase the flux of O2 out of the plant. O2 is a waste product of photosynthesis.

Regards,
Tom Barr