People who run CalRx have to make sure to keep an eye on their CO2 tank and be ready to get it filled on a moment's notice, or if you have a spare full tank, be ready to swap the backup tank for the active one when it runs out. The thing is, CalRx's often end up being a set it and forget it type...
I have a 2 yr old Carbon Doser. Little corrosion around the gauges and fittings and led is a little dim but still works great. Comes with a new co2 hose. $200 shipped within the USA.