[sphelps]

Slow leaks are pretty common for Ca reactors, most people don't even know they have them. Charge your line to double your running pressure, close the tank valve and see if it holds pressure for an hour, if it doesn't you have a leak. You could also have a leak in the actual reactor so you could pressure test that as well but you need to be more careful when doing so. Most reactors on the market are also pretty terrible at dissolving CO2 and/or making the most of it before the effluent, so some reactors are more efficient when it comes to CO2 usage. I would say A 20lb bottle should last about a year on the average system but it's highly variable, one of my previous systems (SPS dominant, 200G total) ran on the same CO2 tank for it's entire lifespan and while that was only around 2.5 years once the reactor was setup and I supplemented with Kalk it gives an idea how long a tank could last. IMO 2 months for 10lbs is way too short and something is off.

For CO2 here in Calgary it's around $30 to $40 for a 20lb bottle and probably not much less for a 10lb. Pretty much everywhere will also charge an extra $10 for expedited service, so you can't wait a week or so it costs more. I now use Oxipro just because they do an exchange system, you just exchange tanks so no waiting and I think it's around $40 but there's no hydro-test or other inspection cost ever added.