Originally Posted by
Rick Cantrell
I may be wrong, but isn't effervescence a white powdery substance found on concrete walls (usually fuzzy looking)?
Effervescence what you get in a glass of water when you drop two alka-seltzer in it.
Efflorescence is the white powdery substance on concrete and leaky pipes. The white stuff is the minerals in the water that remain behind after the water evaporates.
Jeff - my techno-geek term for the stuff in your photo is "a leak".