Q and A: I have a moustache and I have experienced some leakage from the bottom of my mask. Is there any way to prevent this.

You can use a mask seal (do NOT use Vasaline as it can damage some masks).
If you equalize your mask the leakage should not be any greater at depth.
You could also try shaving about an 1/8 of an inch just below your nose. This will give the mask skirt a place to make a seal.
Most drastic option is to go to a purge mask.