Yes, true. That’s how it works for my steel tank. But when I had my (2) aluminum 20 pound tanks, I would not just exchange them for another one because there was no guarantee they’d always have an aluminum one on hand. That’s why I brought them an empty one when I picked up my filled one.
Oh, and I go to an industrial gas supply store. They’re the place that brew shops, bars and restaurants use to fill their tanks. I live in the boonies, but I’m pretty lucky to have a place like this within 20 miles or so. AND, I live near a very popular paintball facility, so as far as my CO2 supplier knows, I fill that big tank to use to fill up our little CO2 tanks for the paintball guns. I even have the filling station used to fill those little tanks and always have it in the back of my SUV so they can see it when I load the tank. We can spend an hour talking about our paint ball adventures, even though I’ve never even shot one paintball in my life. So be prepared to have a reason to get the CO2 if you’re not a legal grower, @SquirtleSquad!
Never had any issues with it, but I did lower my target PPM to 1200 a few months ago.