Re: [GSAS-Member] CO2 blah blah

[Erik Olson <erik@thekrib.com>]

On Tue, 20 Feb 2007, SUSAN WELENOFSKY wrote:

> I thought silicone was better than vinyl. At least, that's what June
> Olberding used, and I got her stuff for taking care of her 20-30 planted
> tank room.

I was talking with some of the Danes from Tropica last year (I think it 
was Claus Christensen back in March, but can't remember), and they said 
that silicone has some of the WORST permeability of tubing out there for 
CO2.  I was surprised to hear that, but it turns out people have been 
saying this for years...I even have an article to that effect from 1999 on 
my own *!&@ website.  Do a search for "permeability of silicone tubing 
CO2" and you'll find a thread on Aquatic Plant Central on the subject! 
They also mention that vinyl has much better specs.

But it's all relative, of course.  Yes, there's lost gas, but exactly how 
much?  Would you notice if you had to replace the cylinder a bit more 
often?  I've used both.  Currently, I use black vinyl tubing (drip line) 
because it's easy to tell the difference between an air and CO2.  Unless I 
can't find any.  Then I use whatever is sitting around.

I wouldn't bother ripping out existing tubing, but if given the choice of 
buying some fancy schmancy new silicone vs. using some old vinyl, go for 
the vinyl.

   - Erik

-- 
Erik Olson
erik at thekrib dot com
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