> ------------------------------ > > My experience with the yeast-sugar CO2 production method is not very good. > When I first set up such a system, it worked reasonably well, but > subsequent batches had been problematic. The bottles of yeast-sugar would > bubble like crazy very quickly and then die out in less than 24 hours. > Adding baking soda and starch helped a little in that some bubbles would be > produced after 24 hours, but the rate is so small as to be useless. Since > yeast (according to my microbiology book) do not produce enzymes capable of > breaking down starch, I figure that any CO2 production must be the direct > or indirect result of contaminants ie. other unknown microorganisms in the > bottle; not a very useful piece of information. > > ------------------------------ Actually, I think the problem could lie in the ingredient mix. I've used the yeast method for my 55g tank for almost a year and each time I can easily get about 2 weeks worth of CO2. (I live in Singapore too, so that should rule out the heat.) The mixture : a 1.5 litre bottle, filled with water to the two-third level. 1/2 cup of sugar, totally dissolved into the water. And 1 teaspoon of instant yeast. Leave to settle for a couple of hours before using. I control the output from the bottle (somewhat) by installing a adjustable airline valve. Hook together 2 or 3 bottles and both stability and output increases. Simple and inexpensive. Hopes this helps. Leng Yee mailto:lengyee at post1_com Jane & Leng Yee's Fish Page: http://www.geocities.com/Heartland/Plains/4433
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