I asked a separate question in the New Mexico group (but it seems to be pretty sparsely populated) so I'll ask a more generic question here if that's OK.
I had a Dennerle pressurised CO2 system in a 55gal tank, 20 odd years ago when I lived in the UK, and am just getting back into planted tanks now. Previously, I used to get the CO2 cylinder (a 5lb I think) refilled at the local fire extinguisher store.
I'm setting up a new system in a 45gal tank, also with a 5lb cylinder, and am trying to figure out where to get it filled. Hopefully, someone has already figured this out in the Albuquerque area, but just in case, I wanted to ask a couple of more generic questions:
- What type of store / facility do you get your CO2 cylinders refilled at?
- Do you insist on food grade CO2, or is a lower grade (e.g. welding / fire extinguisher / paintball gun) acceptable?
I'm guessing what I used to use, being for fire extinguishers, wasn't food grade, and I never had any problems (from what I've read, the principle difference is that lower grade CO2 has larger amounts of other gasses, mostly nitrogen and oxygen), so I'm assuming the issue is principally that you get a little less CO2 for the money, which wouldn't be a big deal, or are there other potential problems (e.g. small amounts of toxic gasses, or other contaminants that might damage / degrade regulators, diffusers etc)?
Thanks very much,