Micro Bubbling

[hig789]

I have been seeing this in a few different places where people deliberately produce micro bubbles into their tanks for a set time daily. I apologize if there is already a thread on this I searched for micro bubbles and didn't get anything in here.

Heres the description on Elegant Corals FB Page. What's your opinion on this Randy?



"Elegant Corals "Micro Scrubbing Bubbles" Technique for the Reef System... :)

Allows the corals to release excess slime and waste...
Allows the coral membrane to breathe and allow for better osmosis and ion exchange with the water column...
Oxygenates the water and de-gasses excess CO2 in the water column out of the system. (Skimmers and a little ball of chaeto is not sufficient... sorry...)

We recommend 8 to 10 hours a day counter cycle for the first week, then 2 to 3 hours a day counter cycle to the display tank lighting to maintain a more consistent and stable pH level.

The correct pH greatly improves the calcification rates of all hard corals...

Oxygenation also assists in higher beneficial aerobic bacterial loads as well as decrease the bad anaerobic cyanobacteria that many hobbyists struggle with.

The micro bubbles also get under (with proper tank flow) dinos and the cyanobacteria and carry them to the over flow to be removed by an efficient skimmer.

Not just for gas exchange or CO2 degassing... part of the nutrient cycle/export system, as well... excellent water flow is needed and vital to prevent the mucus from a neighboring colony to suffocate or burn another. Quick removal with a turkey baster is suggested for stuck on stubborn mucus.

NOTICE: NO FILTER SOCKS IF YOU HAVE A TRUE WORKING REFUGIUM!!

If fighting dinos, cyanobacteria, or other Reef Tank Pests, we will be adding it to our "NOTES" section in the near future!

CHEERS!"

 

[Randy Holmes-Farley]

I agree with some of it, but not everything. Just the words that are written there don't convince me it is worth doing, but as long as it doesn't cause salt spray that gets on lights and electrical and metal parts, then it seems like a fine thing to experiment with and see if it helps in any particular system. :)

How do they make these bubbles?

Increased aeration will stabilize pH, although I'm not convinced that pH stability is typically much of a concern. I'm generally more concerned about the extremes of the daily swing than the swing itself. Especially on the low end. IMO, a tank at pH 7.7 all the time is more stressed than a tank that swings from pH 8.0 to 8.3 each day/night.

The pH will only rise from increased aeration IF the air being used does not itself hold the excess CO2 that is lowering the tank pH. It is often the case that indoor air holds excess CO2, so more aeration with it can actually lower pH and drive in CO2, especially during the day when CO2 levels int he tank are lowest.

I'm not certain that causing corals to release more of their slime is desirable. They make it for a reason. Removing more of it might be useful, but I wouldn't assume it to be true without any evidence. One might think that less slime will increase the rate of exchange of molecules in and out if the slime is reducing water flow in the near coral surface, but again, corals have evolved to produce slime despite the potential reduction in molecule exchange. So is the trade off desirable for them? I don't know. That said, some corals have evolved to live in a surf zone where there is lots of such action naturally. Those probably benefit from it, or are at least not harmed. Others, not normally found in such zones, may not so benefit.

I do not know if increased O2 increases aerobic bacteria. I'd be a bit surprised if it does since O2 levels really don't change tall that much, and may actually drop on increased aeration during the peak of the light cycle where photosynthesis may supersaturate the water.

 

[fab]

There are a lot of posts on a lot of threads on this topic on several forums. All I have seen so far is a lot opinions backed only by what appears to be enthusiasm. I have seen no science on this concept, at least not on its unique feature of being performed in situ. Until someone, or company, performs well designed experiments with proper control cases, documented observations and published analysis, I am afraid this remains in the fad column for me.

A problem I have with this concept is that it appears only to be a variant of a process we already do, and yes, that process works; it works well. What I don't see is any improvement over our current version of the process, protein skimming from with a sump tank. My concern is that micro bubble scrubbing could be less good or even have net detrimental effects. These are the principal questions that need to be answered.

• Is micro bubble scrubbing a process improvement or not? ... to what extent?
• Is it detrimental in any way? ... to what extent?
• What it the net determination?

The differences, either way, need to be quantified sufficiently for aquarists to understand it well enough. We need to be enabled to make informed decisions about incorporating micro bubble scrubbing into our expensive, somewhat delicate aquarium systems. Some aquarists may even consider doing it in lieu of sump-based protein skimming. That would be a decision that should be well-informed, unless the aquarist knowingly falls into the experimental category.

In its essence micro bubble scrubbing appears simply to be protein skimming, just not in a sump. When we do skimming in our sumps, we take pains to rid skimmer effluent of bubbles before they get cycled back into our display tanks. How do they get cycled back? ... through our return pumps. According to the operating principles of micro bubble skimming, these bubbles from skimmer effluent should be chopped up by our return pumps which should, in turn, provide the functionally equivalent scrubbing action when they finally get back into our display tanks. It would just be on an extremely reduced scale. At any rate, the foundation thoughts of tiny bubbles with long dwell times in the water column, slowly rising to the surface causing adherence of 'stuff' to the bubbles so that the stuff can be 'skimmed' away at the surface is not new to saltwater aquarists. We know that works very well. We do it intensively in protein skimmers operating on the water in our sumps as it circulates between display tank and sump.

Therefore it seems that the significant difference between so-called micro bubble scrubbing and our skimmers, which used to be called scrubbers, is mainly in the degree to which the process is performed inside our display tanks versus inside our sumps. A significant difference in the effect of this change of processing venues is the amount of "micro-bubbling" or "scrubbing" action that takes place inside display tanks instead of outside. What we have here is protein skimming under a newly concocted name with undetermined effects of being done rather differently.

One of the problems with the method is the introduction of air bubbles into the intake of a return pump so they can be "chopped up" into the micron size bubbles this "scrubbing" is based on. That sounds to me like it is introducing cavitation effects into the pump's impeller interaction with water. That is known to be bad for pumps mechanically. It degrades them, shortening their useful lives. It can produce noise.

For purposes of experimentation with bubble scrubbing by amateur aquarists, better a separate pump to do that chopping than to risk degradation of a return pump. A separate micro-bubble pipe could be run up to the display tank, keeping this process out of the primary return circuit. A much smaller pump should suffice. Also, borrow from the methods that highly effective protein skimmers use to perform bubble production with venturies and pinwheel mechanisms, not with return pumps sucking bubbles in from an airstone.

If micro bubble scrubbing actually works well and becomes product, efficient and more precise means of producing optimally sized nano or micro bubbles will probably become a discriminator amongst competing products, just as it is in protein skimmers. ...And who knows? Maybe some day 'they' will decide that the next improvement would be to migrate it to the sump, where it can be done as a background process without interfering with the main display tank which is meant to be sparkly clean, clear and beautiful .

 

[fab]

One of the problems with the method is the introduction of air bubbles into the intake of a return pump so they can be "chopped up" into the micron size bubbles this "scrubbing" is based on. That sounds to me like it is introducing cavitation effects into the pump's impeller interaction with water. That is known to be bad for pumps mechanically. It degrades them, shortening their useful lives. It can produce noise.

First, I apologize to the forum member for an error in my post. The offending sentence is emboldened and italicized in the above quoted extract.

Retraction and Correction: The introduction of air does not introduce cavitation to a centrifugal pump's operation.

This air is different to a pump from air that is produced from cavitation. This injected air is known as "entrained" air. Most liquids being pumped have some amount of entrained air, however small.

Some of the details of the mechanisms and their effects of entrained air on centrifugal pump performance are actually widely disputed. That said, it is well agreed that entrained air does not produce the pitting on leading edges and potential the failure of impellers that occurs with cavitation. That pitting happens because the leading edge is essentially pounded upon by the energy released when a cavitation bubble implodes suddenly. Millions of implosions later ... damage.

Entrained air does not do this. Rather entrained air may affect the stability of flow across the impeller which will translate into mechanical instability which produces noise and ultimately mechanical failure. The reason for using the word "may" is these effects and their severity of entrained air are highly dependent on the geometry of the centrifual pump's innards. Relative sizes of volute and impeller blades and casing along with how tight their manufacturing tolerances taken in conjunction with the amount of entrained air in a fluid flow will determine these effects and their severity in centrifugal pumps.

Extremely small amounts of entrained air may actually cushion the blow of imploding cavitation bubbles, reduce pitting and increase the life of a pump that has serious cavitation. The small amount would be well below 1%, by volume, of the fluid (liquid plus gas) flow across the volute and the impeller. Larger amounts of ( greater than 5% or so) will start to produce the mechanical problems that will degrade pump operation, produce unstable liquid flow rate, power consumption, efficiency, pump life and such.

I wrote the original post too concisely for the topic. In doing so I erred in how I tried to explain this particular point. As a result the highlighted sentence in the quoted portion of the post is simply incorrect. I hope this retraction of that sentence along with my corrected version will clarify. Again,I apologize to the forum for this error.

 

[potatocouch]

Need to get Cruz Arias from Elegance Coral to explain/elaborate the concept further.

I had a long chat with him, very informative and very friendly but I'm no chemist expert nor have any science background so I wouldn't be able to comment on his input.

For a normal aquarist like me, all am seeing are + feedbacks. These people can't be and shouldn't be directly associated with him and his company to endorse the concept. We're talking about > 50 people at least.

It may came across to me at some point that this is looking like another marketing gimmick or snake oil, as they'll be releasing device to produce nano bubbles (from memory, it needs to be less than 0.2 micron diameter) but again, he doesn't seem to advertise the product as much, more to the concept itself.

Again, it can be taken either way, + ly or - ly.

If he's in this forum, am sure he be able to explain further and probably Randy can provide some feedback and question some of it. I would see it as a constructive discussion and not a debate :)

If he's not in the forum, if I ask him, am sure he'll be happy to join and post something in this thread. If this is allowed and favoured, I will ask him.

 

[Randy Holmes-Farley]

If he's not in the forum, if I ask him, am sure he'll be happy to join and post something in this thread. If this is allowed and favoured, I will ask him.

Anyone is welcome to post to any thread, and who have significant knowledge on a particular topic are always especially welcome!

The only caveat is that commercial sellers of things must identify that they do so if they comment on what they sell, and they cannot just pop in and push their products if folks are not asking for such info. :)

 

[Rybren]

For a normal aquarist like me, all am seeing are + feedbacks. These people can't be and shouldn't be directly associated with him and his company to endorse the concept. We're talking about > 50 people at least.

R2R user @Thales might beg to differ on the all + comment.

 

[Randy Holmes-Farley]

Need to get Cruz Arias from Elegance Coral to explain/elaborate the concept further.

.

What I'd really like to hear him try to explain are these claims of theirs :D

"Solubility of ions in a solution depend on electro negativity of the solute (water in this case)... water is not just water... it is a stream of life giving electricity..."

and

"The bubbles rubbing up against each other are like balloons or water droplets in the storm clouds... as they pass each other and rub and bump into each other, static electricity is generated... that's the difference between a stagnant dead lake and a dynamic healthy lake... moving water..."

 

[Cruz_Arias]

The topic came up where there was question if positively charged bacteria were attracted to the negatively charged micro/nanobubbles
Just wanted to first share a couple of links showing the net electrical charges of bacteria is present.

http://www.sciencedirect.com/science/article/pii/S0304389414002672
http://www.lenntech.com/library/fine/zeta/zeta-potential.htm
http://www.sciencedirect.com/science/article/pii/S0142961210000979
http://phys.org/news/2013-10-good-bad-bacteria.html

Next... here is the net electric charge of the nanobubble itself...

"The likely reason for the long-lived presence of nanobubbles is that the nanobubble gas/liquid interface is charged, introducing an opposing force to the surface tension, so slowing or preventing their dissipation. Curved aqueous surfaces may introduce a surface charge due to water’s molecular structure or its dissociation. It is clear that the presence of like charges at the interface will reduce the internal pressure and the apparent surface tension, with charge repulsion acting in the opposite direction to the surface minimization due to surface tension. Any effect may be increased by the presence of additional charged materials that favor the gas-liquid interface, such as OH- ions at neutral or basic pH or applying negative ions with an anti-static gun that reduces nanobubble diameter (see below) [2066]. This charge similarity, together with the lack of van der Waals attraction (the cavities possessing close to zero electron density) tends to prevent nanobubbles from coalescence."

Source: http://www1.lsbu.ac.uk/water/nanobubble.html and http://www.idc-online.com/technical_references/pdfs/chemical_engineering/Nanobubbles.pdf

"Measurements obtained with a ZetaSizer Nano equipment showed zeta potential values, in the presence of 102 mol L1 NaCl, displaying sigmoidal pH behaviour between

pH 2 (+26 mV) and 8.5 (28 mV); an isoelectric point was attained at pH 4.5 and were positively charged

(up to 23 mV) in acidic medium, a phenomenon which has not been previously observed. In alkaline

medium, bubbles were highly negative zeta potential (59 mV) at pH 10. The double layers appear to

play a role in the formation of stable nanobubbles providing a repulsive force, which prevents inter-bubble

aggregation and coalescence. Accordingly, the sizes of the nanobubbles depended on their charge and

increased with pH, reaching a maximum (720 nm) around the isoelectric point (±5 mV). Highly charged

and small nanobubbles (approximately 150–180 nm) were obtained in the presence of surfactants

(104 mol L1 of alkyl methyl ether monoamine or sodium dodecyl sulphate); the zeta potential values


in these experiments followed a similar trend of other reported values, validating the technique used

with the nanobubbles sizes varying with pH from 150 to 400 nm. Thus, charged and uncharged stable

nanobubbles can be tailor-made with or without surfactants and it is expected that their use will broaden

options in mineral flotation especially if collectors coated nanobubbles (‘‘bubble-collectors’’) were

employed. A detailed and updated review on factors involving stability, longevity and coalescence of

nanobubbles was made. It is believed that future trend will be on sustainable formation and application

of nanobubbles at industrial scale contributing to widen applied research in mineral, materials processing

and liquid effluent treatment by advanced flotation."

Source: http://www.ufrgs.br/ltm/period_amb/...ties and future applications in flotation.pdf

Hope this helps.

 

[Randy Holmes-Farley]

Ah come on,. this again. :(

No, not helpful.

 

[Cruz_Arias]

Starting? I said thank you for your input the last time. Stop being so argumentative. I'm not disagreeing with you at all...

 

[Cruz_Arias]

You did state:

"What I'd really like to hear him try to explain are these claims of theirs :D

"Solubility of ions in a solution depend on electro negativity of the solute (water in this case)... water is not just water... it is a stream of life giving electricity..."
and
"The bubbles rubbing up against each other are like balloons or water droplets in the storm clouds... as they pass each other and rub and bump into each other, static electricity is generated... that's the difference between a stagnant dead lake and a dynamic healthy lake... moving water..."

So I just stating that bubbles and moving liquids create "electricity" and the links have shown different ways that they are now testing for "minute electrical charges" especially in this case bubbles of a particular size.

 

[Randy Holmes-Farley]

First, you are not forming nanobubbles.

Second, bacteria in seawater have a net negative charge. Your own link is attracting bacteria to positively charged nanoparticles.

Nanobubbles at that pH have have a negative charge accordign to your own links.

So there's no net attraction of bacteria to nanobubbles.

 

[Cruz_Arias]

Thanks for editing that outburst... there is validity to the science... it is still a relatively new field of study, so "proof" is still being worked on... we have a few SBIRs in the works as well... so in a few months we should have some pretty good data and information.

 

[Cruz_Arias]

First, you are not forming nanobubbles.

Second, bacteria in seawater have a net negative charge. Your own link is attracting bacteria to positively charged nanoparticles.

Nanobubbles at that pH have have a negative charge accordign to your own links.

So there's no net attraction of bacteria to nanobubbles.

Depending on which bacteria we are speaking about, can have a negative or positive charge.
http://phys.org/news/2013-10-good-bad-bacteria.html

If the bacteria has a net positive charge, it will be attracted to the net negative electrical charge of the nanobubbles...

The term "Micro-Nanobubble" is an in between size, Randy. True nanos are less than 50um... micro-nanos are typically around 50 to 100um... and microbubbles are typically 100um or larger...

We are getting a mix of bubble sizes at the moment... regardless of how crude the method... it's all about fluid mechanics and how it is generated.

 

[Randy Holmes-Farley]

You did state:

"What I'd really like to hear him try to explain are these claims of theirs :D

"Solubility of ions in a solution depend on electro negativity of the solute (water in this case)... water is not just water... it is a stream of life giving electricity..."
and
"The bubbles rubbing up against each other are like balloons or water droplets in the storm clouds... as they pass each other and rub and bump into each other, static electricity is generated... that's the difference between a stagnant dead lake and a dynamic healthy lake... moving water..."

So I just stating that bubbles and moving liquids create "electricity" and the links have shown different ways that they are now testing for "minute electrical charges" especially in this case bubbles of a particular size.

What you say has nothing to do with the actual scientific reason and evidence of why nanobubbles have a negative charge (which has to do with the crowding of different ions ions at the tiny curved surface and the fact that hydroxide ions are slightly more prevalent there than H+ ions).).

 

[Randy Holmes-Farley]

Depending on which bacteria we are speaking about, can have a negative or positive charge.
http://phys.org/news/2013-10-good-bad-bacteria.html

Can you point to where this link suggests bacteria have a net positive charge at pH above 7?

I don't see any data or comment on charge at all.

 

[Randy Holmes-Farley]

We are getting a mix of bubble sizes at the moment... regardless of how crude the method... it's all about fluid mechanics and how it is generated.

But not nanobubbles small enough to have the negative charge you are touting (although I can hardly understand why that's important since it doesn't do anything useful for an aquarium that I can see).

 

[Cruz_Arias]

But not nanobubbles small enough to have the negative charge you are touting (although I can hardly understand why that's important since it doesn't do anything useful for an aquarium that I can see).

In your tank or ours, Randy?

 

[Cruz_Arias]

Can you point to where this link suggests bacteria have a net positive charge at pH above 7?

I don't see any data or comment on charge at all.