Skimmer or Refugium

[Lasse]

This also explains why things like Melafix (containing oils in a water-soluble form) and soap are removed by protein skimmers.

They are not removed in a concentrated form in the foam -they cause the foam to collapses (the concentration mechanism) and many times make the skimmer overflow and the concentration in this overflow out in the skimmer cup is the same as in the water column. It is a type of WC.

Freshwater skimming will not concentrate unwanted compounds very well but for brackish water it works sometimes even for some nonpolar compounds. Skimming in saltwater above 25-30 PSU only works for amphiphilic substances (read mainly proteins) - but on the other hand it works very well.

protein skimmer to produce more foam are not necessarily removed by them

The foam consist of concentrated substances - proteins in water above 25 - 30 PSU are one example. But those substances you mentioned does not produce more foam (IME) in this type of saltwater - they make the foam to collapse - which means concentrations not much above the concentration in the water column.

Sincerely Lasse

 

[Privateye]

They are not removed in a concentrated form in the foam -they cause the foam to collapses (the concentration mechanism) and many times make the skimmer overflow and the concentration in this overflow out in the skimmer cup is the same as in the water column. It is a type of WC.

Freshwater skimming will not concentrate unwanted compounds very well but for brackish water it works sometimes even for some nonpolar compounds. Skimming in saltwater above 25-30 PSU only works for amphiphilic substances (read mainly proteins) - but on the other hand it works very well.


The foam consist of concentrated substances - proteins in water above 25 - 30 PSU are one example. But those substances you mentioned does not produce more foam (IME) in this type of saltwater - they make the foam to collapse - which means concentrations not much above the concentration in the water column.

Sincerely Lasse

I'm still not understanding something. If amphiphilic molecules are removed by protein skimmers (in a concentrated form) then why wouldn't soap be removed? It's amphiphilic. Or in the case of Melafix, an emulsified oil.

Part of this line of questioning is I'm wondering whether a protein skimmer "accelerant" would be a viable product for our industry.

 

[Lasse]

in a concentrated form in the foam

If amphiphilic molecules are removed by protein skimmers (in a concentrated form) then why wouldn't soap be removed? It's amphiphilic

As I try to explain earlier:

The high ion concentration together with the tiny bubbles in a skimmer force those amphiphilic substances to the air/water surface of the bubbles. (thermodynamic driving force / "salting-out") Upon reaching this interface , they undergo surface denaturation, whereby the hydrophobic end attaches to the gas phase at the interface and the hydrophilic end attaches to the water. What happens next is that the amphiphilic substances form a rigid, viscoelastic network (intermolecular cross-linking/gel formation) that stabilizes the foam which builds up and is transferred into the skimmer cup. This is mainly proteins but some other larger amphiphilic substances may also be a part of this network.

On the other hand - detergent molecules are significantly smaller and diffuse more readily, they move faster toward the air-water interface, thereby physically displacing the larger amphiphilic substances (competitive adsorption).

Within the water column itself, detergent monomers encapsulate the larger amphiphilic substances. This masks the non-polar regions of these substances, neutralizes the "salting-out effect," and eliminates the thermodynamic driving force that causes the amphiphilic substances to migrate toward the air bubbles (macromolecular solubilization).

The result will be less stable foam - lesser concentrations of "unwanted" substances. If the skimmer will "overrun" because of this type of substances - the concentrations of all substances is the same in the "overrun" as in the water column

If we talk about soap only - its true that it is amphiphilic but in a water rich in Ca and Mg - mostly Ca bounds to the soap molecule - and form sticky precipitate on all surfaces. Instead of forming a clean micelle this chemical reaction creates an insoluble, sticky precipitate commonly known as soap scum. (micelle is the tiny sphere formed by the amphiphilic soap , keeping the oil or fatty particles trapped on the inside and the water-loving heads exposed on the outside),

This sticky sticky precipitate - calcium soap ((RCOO)₂Ca) is completely insoluble in water - stick on surfaces - As far as I know, this precipitate will not incorporate other substances—only calcium and magnesium.

This reaction have nothing with a skimmer to do - it happen directly when the soap molecule enters the saltwater.

Sincerely Lasse

 

[Privateye]

As I try to explain earlier:

The high ion concentration together with the tiny bubbles in a skimmer force those amphiphilic substances to the air/water surface of the bubbles. (thermodynamic driving force / "salting-out") Upon reaching this interface , they undergo surface denaturation, whereby the hydrophobic end attaches to the gas phase at the interface and the hydrophilic end attaches to the water. What happens next is that the amphiphilic substances form a rigid, viscoelastic network (intermolecular cross-linking/gel formation) that stabilizes the foam which builds up and is transferred into the skimmer cup. This is mainly proteins but some other larger amphiphilic substances may also be a part of this network.

On the other hand - detergent molecules are significantly smaller and diffuse more readily, they move faster toward the air-water interface, thereby physically displacing the larger amphiphilic substances (competitive adsorption).

Within the water column itself, detergent monomers encapsulate the larger amphiphilic substances. This masks the non-polar regions of these substances, neutralizes the "salting-out effect," and eliminates the thermodynamic driving force that causes the amphiphilic substances to migrate toward the air bubbles (macromolecular solubilization).

The result will be less stable foam - lesser concentrations of "unwanted" substances. If the skimmer will "overrun" because of this type of substances - the concentrations of all substances is the same in the "overrun" as in the water column

If we talk about soap only - its true that it is amphiphilic but in a water rich in Ca and Mg - mostly Ca bounds to the soap molecule - and form sticky precipitate on all surfaces. Instead of forming a clean micelle this chemical reaction creates an insoluble, sticky precipitate commonly known as soap scum. (micelle is the tiny sphere formed by the amphiphilic soap , keeping the oil or fatty particles trapped on the inside and the water-loving heads exposed on the outside),

This sticky sticky precipitate - calcium soap ((RCOO)₂Ca) is completely insoluble in water - stick on surfaces - As far as I know, this precipitate will not incorporate other substances—only calcium and magnesium.

This reaction have nothing with a skimmer to do - it happen directly when the soap molecule enters the saltwater.

Sincerely Lasse

I wanted to circle back to provide an update. The past week has been quite busy, but I eventually took the time to look into your response. Basically I think at this time I should drop the discussion and do more reading. Your AI is providing a lot of new information for me, which I truly appreciate. My sources just still seem to conflict on the topic of soap removal. I've found journal articles that say both anionic detergents and cationic detergents are removed by foam fractionation. This article isn't one of those I'm referring to, but it's probably the most-relevant I found (focused on surfactants):

https://pubs.acs.org/acsodf/article...-Fractionation-as-an-Efficient-Method-for-the

Later I tried turning to AI as well to help speed-up my understanding. When asking Gemini and ChatGPT whether soap, detergents, surfactants, and Melafix are removed by protein skimmers they tell me yes for all of them, but I don't take it as gospel. I then tried putting your latest response into ChatGPT for a fact check and it gave me a chart with results on each point. 4/11 were correct, 3/11 were incorrect, and the rest were overgeneralized, unsupported, or used incorrect terminology. Mostly "I know what you mean" situations though. Those aren't very significant to me. I'd be an ___hole for nit-picking them.

I have limited trust in free AI, yet I simply don't know enough at this point to refute some of the claims without it. I'd be willing to send you the chart directly if you like, but the goal of this post is not to prolong the debate via AI. It's to let you know that I intend to get a better background in these concepts, which this discussion stimulated. Maybe the topic will resurface later on, but for now I appreciate you teaching me some new things.

All the best,

PI

 

[Nixperience]

I ended up getting a Bubble Magus Mini Q and I’m very impressed. It’s been running less than a week and almost through breaking in. It’s very quiet and actually skims quite well and it’s super tiny. A Refugium would’ve been awful in that compartment. I feel like it will help me with a heavier bioload or heavier feeding for sure.