Neptune Aquatics

Skimmer in freshwater Q

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I was testing my sump yesterday running it with fresh water, set couple skimmers, first a BM200 and noticed the pump did not produce good enough air/water mix so I thought it was a bad pump, impeller? Skimmer is fairly used.
Then puller out another one, a BK160 and same thing with the bubble producing issue.
I have never run a skimmer in fresh water, Could the issue be the fresh water?

Thx
 
Yes pumps can't produce as much bubbles in FW. I did the same thing when I got my used skimmer and I thought the pump was bad but once put in SW it worked just fine.
 
simple explanation: foaming requires something in the water to help keep its shape. In SW, that is from phospholipids and proteins etc. These "foam stabilizers" are absent in FW.
 
To get a skimmer to work in freshwater requires a much smaller neck. The ones on the market use a couple 1" tubes (on a 12' unit).
 
Thanks for the input, I figured by using RODI water to test them might have been the reason, after all, was there anything in the water to skim out?
I thought the Sicce pump needed at least a new impeller but if it happened on the BK and ER must have been the water.
 
It's not just about skimming stuff out. Salt makes the water denser. It's like trapping bubbles in syrup compared to alcohol.
 
Not to get too technical, but it isn't density. It's viscosity, which plays into surface tension, which plays into surfactants etc (which are the phospholipids and proteins).
 
Funny thing is... my analogy was spot on for viscosity (and I knew that :( )
 
Gomer said:
simple explanation: foaming requires something in the water to help keep its shape. In SW, that is from phospholipids and proteins etc. These "foam stabilizers" are absent in FW.
Click to expand...

Hmm, are you sure about this Tony? I mean, there are phospholipids and proteins in freshwater too, right?

I always thought that the reason skimming didn't work in FW is because you can't create very small bubbles, and that the ability to create smaller bubbles in seawater had to do with the ions and their effect on surface tension.
 
yes, that is a part of it. Its all about surface tension and surfactants. Ions (as in salt) don't do much directly (afaik), however polar organics (and more so, things that behave like zwitter ions and organics with polar and non-polar groups) are the key players. I would venture a guess that the pH plays a pretty big roll with any given organic in water. Salt water, laden with certain salts, results in a fairly basic solution which likely favors de-protination. I'll see if I can find some papers on this tomorrow to either enforce or refute all I said lol.
 
Matt_Wandell said:
Gomer said:
simple explanation: foaming requires something in the water to help keep its shape. In SW, that is from phospholipids and proteins etc. These "foam stabilizers" are absent in FW.
Click to expand...

Hmm, are you sure about this Tony? I mean, there are phospholipids and proteins in freshwater too, right?

I always thought that the reason skimming didn't work in FW is because you can't create very small bubbles, and that the ability to create smaller bubbles in seawater had to do with the ions and their effect on surface tension.
Click to expand...


Sure we are going to miss Tony...
HEY !! but here's Matt !!
 
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