Re: CO2 with undergravel filter?

>Date: Wed, 2 Aug 1995 23:34:24 -0500 (CDT)
>Subject: C02 into undergravel filter?
>I'm thinking of adding DIY yeast CO2 to a 29 gallon tank.  The tank has an
>undergravel filter with a power head.  Has anybody tried sticking the CO2 hose
>into an undergravel filter in order to mix the CO2 into the tank water?  The
>tank has java fern and mexican oak leaf attached to drift wood; so no comments
>about undergravels being bad for plants :)  I guess my main concern is that 
>that white stuff that builds up at the end of the CO2 hose from yeast systems
>would be a problem in the undergravel.


depending on your KH (buffering ability) you might find that putting CO2 into
the powerhead will cause a rapid pH drop - I did when I tried this in my 125
gal tank.  I had been just bubbling the CO2 into a Tetra Diffusion Chamber
and I went back to doing this.  I suggest you try either using a chamber (you
can just used an upturned cut-off soda-bottle-bottom) or an airstone to see
what effect on pH you get.  In my 25 gal tank without UGF, I just use this
method & I have to turn an airstone on overnight to avoid CO2 gettting too
high & pH too low overnight (& thats with a KH of 8!).

I never had a problem with white stuff on my CO2 hose though - are you leaving
a good 2-3" airspace at the top of your bottle to allow for foaming/frothing
of the mixture so that it doesn't get into your tank?  Also, I'm careful not
to shake it so much so that mixture does not go into the tank.