Okay I'm out for about 7-8 hours. No sleep, I just had to keep up with this co2 stuff, unfortunately it seems like I can't go on now, need the rest...
Forget hardware stores or even places that refill tanks.Aquariun co2 is not common except for with aquarium hobbyist.Just dealing with Rex is your best bet.
The problem was not the low pressure gauge.Welding supply store are a good local alternative for parts and repair. They likely won't touch Milwaukee/JBJ regulators, but they'll probably be willing to have a look at Rex/Greenleaf regs. Alternatively, they'll have the appropriate gauges for replacement. Just take the reg in and tell them you need to replace your low pressure gauge. They'll sell you the right thing and possible just throw it on there for you.
CO2 is CO2....sure, we use solenoids and bubble counters, but the principles of the regulator are all the same.
The problem was not the low pressure gauge.
JM was just clarifying the point to another user that our equipment can be fixed at a Welding supplier, since we technically get our gear from welders in the first place.The problem was not the low pressure gauge.