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Re: Protein skimmers (was: box filter)



>
>Protein skimmers (aka foam fractionators) are not particularly effective in 
>fresh water, primarily because of the size of the airstone bubbles when 
>compared to salt water.  I am cautious to say they won't work at all,
because 
>I had some incidental fractionation with my air-pwered RUGF that left brown 
>skimmate stains on the wall from DOCs that atomized as the bubbles broke in 
>the top of the tubes.
>
>Peter, do you know a way to improve their efficiency in fresh water, either 
>by reducing bubble size, or other means?
>
>Bob Dixon
>
I tried building a few using limewood diffusers, which produce a smaller
bubble than the normal blue airstones.  The stones are hung inside a 2"
polystyrene measuring dispenser glued to the bottom of the skimmer. Their
efficiency depends on skimmer height and diameter, flow rate and the right
relation between air flow and water flow - which I dont seem to have found
yet. My first two attempts are horrible square contraptions that work great
removing the greasy film on the tanks.  They are fed by a line coming from
a small funnel that hangs underneath a piece of u-shaped styrofoam, to
collect surface water.  Definitely not something you want in a display
tank.  Contraption No. 3 was made from a cilindrical polystyrene spaghetti
jar and it looks a little more like aquarium gear, but is a royal pain to
adjust the flow.  When it works for a few hours in a row, it does expell
brown foam.  Again, to avoid having to adjust the height of the collecting
cup, I used a styrofoam ring with an inverted plastic funnel (actually the
neck of a break fluid bottle, cut diagonally, so the muck oozes out to the
side without having to attach yet another cup on top).  I guess the results
are pseudo-satisfying because when I remove the greasy surface film,
theres enough organic material + fatty acids to form bubbles that actually
travel through the top.
Im just finishing building a mold to cast 4" acrylic tubes, 30" long,
which I hope should be easier to work with to try to remove dissolved
organics, rather than only the ones that float on top.  They should work
great in freshwater, but Im not there yet.

Peter



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