Thanks for the reply. Hopefully I got a good deal, cause I ordered a regulator last night! It's a Victor VTS250c reg, dual stage. I think, if I've been looking at the right threads, I'll need to replace the adapter with one for co2 tanks, and then add the extra equipment to make it usable in the tank, but it seems this is one that people have used before for this. It was $45, and looks to be in pretty pristine condition. Do you think $45 is a good deal?
A reasonably good deal.
I think I'll need to replace the working pressure indicator, as this one is up to 200, and I've seen most people want one that goes up to 100, so they can better dial in their working pressure.
If the gauge goes from 0-200, then there will be a minimum working pressure as well (check the product specification sheet). Some of them can only go down to (say) 10 PSI, which might not be suitable for smaller aquariums.