Co2 question

> 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!