I haven't gotten my CO2 started yet, but I do brew beer at home and www.ebrew.com
(Alternative Beverage) carries wine-making supplies as well as beer brewing supplies. Here's a link to the champagne yeast: http://www.ebrew.com/wine/wine_yeast.htm#L-EC
I suppose one could COMBINE home brewing and aquarium enthusiasm to hook up the CO2 system to a brewing batch of beer, but somehow I suspect that 5 gallons of fermenting stout might throw off a bit more CO2 than my 29 gallon tank really needs. You'd also have the problem of needing to have a batch brewing constantly...but then that's not really so much of a problem, really, is it?
Will the Hagen do the trick for a 29 gallon, using a home-made yeast recipe? I saw elsewhere that it was only recommended for tanks up to 20 gallon, but then I've seen a lot of people here using it for 30+ gallon tanks. Thanks for any info!