Quote Originally Posted by SoLiD View Post
The smooth side goes on the glass. Inside the tank of course.
Dayum....just when i thought I had the mystery solved. This is what I saw on Saltwaterfish.com:
Quote Originally Posted by saltwaterfish.com
Just to let you know, the gasket has two rings on one side of it and none on the other side. You should put the flat side facing the lip and the two rings facing the glass of the aquarium. The two rings create a much, much better seal then the flat side.
I had it installed the way you said, but can't remember how the other 5 were installed. I just opened the bags up and put them on the tank. I'll have to try again in the morning.

Thanks for the response.