CO2 Bends

> From: "Olive K. Charlsey" <achaudh at emory_edu>
> Date: Sun, 26 May 1996 16:04:56 -0400 (EDT)
> If you have read the article at:
> http://www.cco.caltech.edu/~aquaria/Krib/Plants/CO2/co2-bends.html
> > I have played with some similar CO2 systems - they are not too efficient
> > which is good - less chance of overdosing.  Today, I was talking with
> > John Burleson (with Dupla).  I asked him about his reactors - too
> > efficient to use without a controller.  When I told him of the filter
> > idea (I am currently doing it with an eheim), he said there may be some
> > problem because of the change in partial pressure as the co2 laden
> > water exits from the filter.  He thought this caused the CO2 to dissolve
> > instead of converting to carbonic acid.  Neither one of us knew enough
> > to understand what is really happening, but he assured me that he
> > discussed this with reliable sources and thought this is discussed in
> > one of Spotte's books.  The problem is that the dissolved CO2 can cause
> > an embolism, like the bends for divers.  This may be a good topic for
> > the net.
> Any thoughts? Am I missing something here?

No much.

Yes, Dupla reactors are very efficient and should be used with a

> CO2 does dissolve in water to form H+HCO3-. There is no other way that it 
> dissolves, no matter what pressure, no matter what the concentrations. 
> So, what are they talking about in that message?


In regards to asking a reactor vendor about NOT using his products:

  Uh-huh.  Clueless or trying to generate Fear, Uncertainty and Doubt

For the CO2 to supersaturate (if that was possible), you would
need higher pressure in the filter.  The only significant extra
pressure you will see is due to the head of the water above the
canister filter, which may be 48" to the surface of the tank and maybe
24" from the bottom of the tank.  I don't think scuba divers worry
about the bends in 4' of water.  

"Discussed with reliable sources" indeed.  FUD, clear and simple.

George in Wet and Mucky Colorado