abark
Member
Large bubbles that are produced during dry skimming, at the top of the neck, do not have the surface tension to suspend large particulate matter. If the level you set in your skimmer is say hypothetically 4" below the riser cup to produce dry skimmate, the weight of the particulate matter that reaches the top will eventually not be able to support the types of bubbles produced during dry skimming. Sadly, I have spent many hours watching my skimmer and the types of bubbles that spill over the neck during wet skimming and dry skimming are vastly different.
During dry skimming it is a compounding effect that occurs on a molecular level. The bubbles that pop release organic material that is able to be suspended by the surface tension of the bubbles below it. Therefore, as the bubbles release more and more organic matter it builds until it can spill over. While this is not a bad thing it does require a breakdown of some sort which is usually accomplished in the tank in the form of an organic breakdown. As long as your skimmer is big enough it will be able to take it out by this method eventually, and probably before it causes any kind of harm to your tank. The only problem I have observed with dry skimming is that the bubbles pop in the neck and stick to the riser which requires frequent maintenance. The stuff that sticks to the neck is pure sludge and the stench is unbearable. I would say that this is definately accomplishing something, along with the dark stank that is in my collection cup.
With wet skimming the bubbles rise to a high enough level then spill over, hopefully not too quickly where you are pulling out a solution low in organics. The one good thing about the bubbles that are allowed to reach the top of the riser is that they have the ability to suspend particulate matter until it can reach the top of the collection cup. This is due to the increased surface tension that is a result of water/bubbles that is low in organic molecules that can impede the natural ionic bond that are created by the properties of water's ionic nature. Look at pure water and watch the meniscus effect, now try changing the chemistry of the water (with organics and not electrolytes) and see if the meniscus effect is nearly as strong. When I skim wet there are a lot of particles in the cup that would end up in my tank to eventually break down. Yes, I skim wet because of this. I would rather it break down in my cup than in my tank.
My last comment is refuting possible arguments to statements I have made previously. Salt will actually increase the surface tension of water by introducing charge into the water by releasing + and - ions into the water which will actually attract the molecules more than in pure water. This is why our skimmers work effectively in salt water but not in fresh water. If you have ever run your skimmer in a rubbermaid in freshwater you know what I mean.
Here is a graph to illustrate my point.
Here is a decent link
http://www.ucalgary.ca/~schramm/explan.htm
During dry skimming it is a compounding effect that occurs on a molecular level. The bubbles that pop release organic material that is able to be suspended by the surface tension of the bubbles below it. Therefore, as the bubbles release more and more organic matter it builds until it can spill over. While this is not a bad thing it does require a breakdown of some sort which is usually accomplished in the tank in the form of an organic breakdown. As long as your skimmer is big enough it will be able to take it out by this method eventually, and probably before it causes any kind of harm to your tank. The only problem I have observed with dry skimming is that the bubbles pop in the neck and stick to the riser which requires frequent maintenance. The stuff that sticks to the neck is pure sludge and the stench is unbearable. I would say that this is definately accomplishing something, along with the dark stank that is in my collection cup.
With wet skimming the bubbles rise to a high enough level then spill over, hopefully not too quickly where you are pulling out a solution low in organics. The one good thing about the bubbles that are allowed to reach the top of the riser is that they have the ability to suspend particulate matter until it can reach the top of the collection cup. This is due to the increased surface tension that is a result of water/bubbles that is low in organic molecules that can impede the natural ionic bond that are created by the properties of water's ionic nature. Look at pure water and watch the meniscus effect, now try changing the chemistry of the water (with organics and not electrolytes) and see if the meniscus effect is nearly as strong. When I skim wet there are a lot of particles in the cup that would end up in my tank to eventually break down. Yes, I skim wet because of this. I would rather it break down in my cup than in my tank.
My last comment is refuting possible arguments to statements I have made previously. Salt will actually increase the surface tension of water by introducing charge into the water by releasing + and - ions into the water which will actually attract the molecules more than in pure water. This is why our skimmers work effectively in salt water but not in fresh water. If you have ever run your skimmer in a rubbermaid in freshwater you know what I mean.
Here is a graph to illustrate my point.
Here is a decent link
http://www.ucalgary.ca/~schramm/explan.htm
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