CO2 diffusion and Fluval filters

>From: ac554 at freenet_carleton.ca (David Whittaker)
>Date: Wed, 14 Feb 1996 05:13:09 -0500
>Subject: Re: CO2 Questions

<stuff deleted>

>For the Internal Fluval Filters just drill a hole in the clear
>plastic filter cover and attach the airline hose via a nipple
>or a mini airline connect. The CO2 bubble that forms is slowly
>dissolved as water is sucked through the sponge filter.

This leads right into a question I was going to ask.  I've been trying to
decide how I want to diffuse CO2.  I had originally planned to build a
diffusor and hook it inline with my Fluval 403.  Then I thought it might work
to simply run the CO2 into the intake hose of the filter, and let the filter
do the diffusing.  The impeller in the Fluval is at the end of the water path,
not the beginning.  That is, the impeller "pulls" the water through the filter
instead of pushing it.  The result would be that the CO2 bubbles would never
come in contact with the impeller (not a bad thing in itself) and would be
trapped by filter media.  A friend of mine expressed concern that since the CO2
bubbles wouldn't be broken-up, they wouldn't dissolve fast enough and a large
CO2 bubble would form inside the filter.  Anyone have any thoughts about this
or actually tried it with a Fluval?  Any help appreciated.
| Mark A. Thompson   | Certified OS/2 Engineer                               |
| rrs0062 at ibm_net    | OS/2 Advisor (Talklink OS2BBS)                        |
| St. Peters, MO USA | "You can't fight Evil with a macaroni duck!" - Arthur |