> From: 'jcogges at ssp_jsc.nasa.gov' > > I have a 90 gallon tank and the salesman estimated my bottle would > last 1-2 months. I would be very interested if you would carefully track your usage. We had 4 chambers in a 55 gallon tank and could not get enough CO2 diffused (we're at high altitude, though). We have a 20# tank and an automated CO2 system on our 90 gallon tank and that lasts about 15 months (about 20 oz per month). Good luck on the new tank! George