Hello,
I just bought a replacement o-ring that seals the canister of my old XP2. I know a lot of people on here use that type of filter, so I'm hoping someone can answer a stupid question.
The o-ring I was sent from PlanetRena has 2 sides with a deep groove running down the center, and 2 sides with a small ridge down the center. Which side goes up?
I assumed the grooved side goes up so the edge of the canister can sit in it, but when the o-ring sits flat, the groove is naturally on the side. The instructional video I found online talks about a "ridged side" and a "flat side" so I'm confused. Mine doesn't have a flat side. Unfortunately I didn't pay enough attention when disassembling the original o-ring.

