I have a co2doctor[0,1] kit, a 20lb capacity tank from amazon (bought new - you can get them used but then you don&#x27;t know where they&#x27;ve been or how clean they are...) and filled it for about $30 at Carbonic Service[2] in Santa Clara.<p>0. <a href="http:&#x2F;&#x2F;co2doctor.com&#x2F;" rel="nofollow">http:&#x2F;&#x2F;co2doctor.com&#x2F;</a> (site down at the time this comment was posted)<p>1. <a href="http:&#x2F;&#x2F;www.ebay.com&#x2F;sch&#x2F;co2doctor&#x2F;m.html?_nkw=&amp;_armrs=1&amp;_ipg=&amp;_from=" rel="nofollow">http:&#x2F;&#x2F;www.ebay.com&#x2F;sch&#x2F;co2doctor&#x2F;m.html?_nkw=&amp;_armrs=1&amp;_ipg...</a><p>2. <a href="http:&#x2F;&#x2F;www.yelp.com&#x2F;biz&#x2F;carbonic-service-santa-clara" rel="nofollow">http:&#x2F;&#x2F;www.yelp.com&#x2F;biz&#x2F;carbonic-service-santa-clara</a>