[nullset]

I have a 2007 328xi, with ~66k miles.

I drive it fairly irregularly, a couple times a week. I drove it about 130 miles on Saturday, with no issues that I noticed. No warnings, etc.

On Wednesday, it snowed, and I share a driveway with my neighbors, so I had to move my car to clean around it. I left the car running/warming while I cleaned it off (probably ~10min). When I was finished I put my car back and noticed a small amount of coolant in the snow. The next day (after the car had cooled down) I checked the coolant reservoir and it was low. The stick was not poking out at all (still visible, the top was about flush with the top of the reservoir).

So, I'm wondering if I should fill the reservoir with 50/50 and check for any obvious leaks, then run the bleed procedure (with the holding the gas pedal in for 10 seconds, etc), and check for leaks again? Sadly I'm in an apartment and don't have a jack or ramps, so my best option is just to take it somewhere, but I wanted to make sure it wasn't an obvious hose before I did that.

Some info:
-I did the water pump and thermostat over the summer. I haven't had any issues since then.
-A BMW mechanic did the reservoir sensor not too long ago, so I have some faith that that's working correctly, and it makes me guess that the leak isn't related to my changing the pump/stat because I figure it would have given me a low-coolant warning or overheated by now.
-I used blue BMW coolant, while the stuff that leaked was more of a neon greenish color. Any ideas on the issue here? I had some left over from the second gallon I bought when I did the water pump, and I poured it in some snow (I cleaned it up, I promise) and it was definitely a different color.

Thanks everyone, I'm going to fact-find more tonight, but I wanted to see if anyone thought I was missing something, etc.