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"It doesn't really work on freshwater. The reason it works on saltwater
is just that. The
skimmer removes proteins and waste that float in the solution due to the
of the water. Much like it is easier for you to float in the ocean than
it is for you to float
in freshwater, it has to do with the density of the water."
Bob is repeating one of those old myths that plague our hobby. Bob should tell it to the first users of the skimmer when it was only used for fresh water. A skimmer works by creating lots of air/water interfaces. It has nothing directly to do with salinity though salinity affects bubble size and therefore the amount of air supply needed to get a given amount of foam. It has nothing to do with floating. In fact an air/water mix has a low density whether salt, brine, or fresh. An object such as a floating thermometer or hydrometer would rapidly sink to the bottom of an air/water mix such as found inside a skimmer. Try it Bob.
The molecules removed by skimming have a side that is attracted to water but another side that is repelled by water. They naturally line up on an air/water interface with their water-loving ends in the water and their hydrophobic ends in the air. Foam contains more of these molecules than the rest of the water, so by removing the foam, you remove them too. Typically they are proteins so the process is called Protein Skimming. The old name Foam Fractioning was perhaps more accurate since other things than proteins might be removed too.
----- Original Message -----
From: Bob Woth
Sent: Thursday, September 05, 2002 9:41 PM
To: killietalk at aka_org
Subject: Re: Skimmer
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