I probably just haven't looked in the right place, but can someone point me to Tom's plans for the external reactor? I've seen the article in the public part of the website on the internal venturi reactor, but can't seem to locate the plans for the external.

Couldn't find them in the July 2005 newsletter (which was suggested somewhere here). (I also realise there are other options like misting, which I've been looking into as well.)

Edit: this post should probably be in the diy section, sorry.

Edit No. 2: Oops, just found the update and in this section of the board as well. Looks as if it's still coming

Ive built a reactor that works both as a normal reactor but also as a mist device.
Here are some pictures of it, however ive written everything in Swedish.
http://plantswap.forum24.se/plantswap-about100.html
Its a very simple design. But most important is the diffusion of CO2 in the "chamber". Im using a ADA style diffusor which ive cut down to a shorter length. The finest bubbles goes straight out into the aquarium to produce a fine mist. The rest dissolves inside the "chamber". Since im not a fan of mist the only thing I have to do is reduce waterflow so the finest bubbles wont go straight ito the aquarium.