So I turned the second regulator gauge all the way open(so no co2 would run through it)
I don't understand this statement. Regulators control pressure, not flow. If you ran the adjustment screw all the way in (CW), you've maxed the pressure, which is what your gage indicates. When the line from a regulator is not connected to a keg, there should be no flow, regardless of the pressure setting.
Try reducing the setting to the minimum (CCW) and leave the line unattached. If this is what you meant by "all the way open", then you probably do have a defective regulator. Most likely the diaphragm is damaged.
By the way, when checking for leaks, it is a good idea to shut the tank valve after pressurizing the regulators & lines.
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