Mysterious coolant leak

Hello again,

I've had an issue for a while now and I haven't been able to find it.
It's been losing small amounts of coolant here and there, and the thermostat was stuck open.
Every now and then I'd top off the reservoir is the level got so low, but recently I replaced the thermostat with a 193°F (manufacturer suggests 195°F) thermostat, I figured a couple of degrees wouldn't make much difference, I made sure to bleed the system and kept a close eye on the housing, I even replaced the top hose to be on the safe side.
So since the thermostat has been put in it's losing coolant faster now. I checked the housing and hoses a thousand times and it's all bone dry.
There's never a drop of coolant on the ground and it's always parked in the same spot every day.
The hoses to/from the firewall are dry, the floorboards are bone dry, there's also no smell of coolant inside or outside of the car.
The oil is still clean like it was changed yesterday and it was changed over a month ago.
There's no signs of oil in the coolant, no sign of coolant on the oil fill cap, no steam out of the tailpipes, not a drop of coolant on or around the water pump, radiator is bone dry outside, so are all the hoses, nothing underneath the car, nothing on the outside of the coolant reservoir.
I don't know if I'm missing something.
The antifreeze is prestone 50/50, car doesn't overheat even a bit, doesn't run rough, no trouble codes. There was no sign of coolant on the spark plugs.
I searched and asked the charger forums and one suggested testing the coolant, and doing a compression test. I wanted to do a coolant system pressure test, the kits are expensive though.
This is the only leak the car has, no oil or transmission leak, no power steering leak.
What should I do?
Thanks!