After noticing a stain under a toilet bowl set on a concrete floor I decided to replace the toilet as it was overdue to be replaced anyway. When the new bowl and wax ring failed to stop the seepage (nothing visible when flushing but an ever expanding stain would later appear) I doubled up the wax rings. That lasted about a year. Now the same growing stain has returned. No blockages. Flushes normally. Copper flange looked good a year ago. Not set too high or too low. What am I missing? Could the concrete be causing condensation? Thermostat set at 70. I'm at a loss (not the first time and definitely not the last! ). Thanks.