Maybe just call Hagan on Monday and have them ship you a periodic maintenance kit with a new ring.
Do you see any cracks in the lid?
Hagan Customer Service - Caren is one CS rep. really nice 800-724-2436 This is the number I got via email to order if I needed something (saw a different one online). USA phone number.
New to FW fish? First tank in a long time or EVER??? Need some info on keeping fish?
Start here - Aquarium Advice Article
FW Favorites right now Clown Loaches, any shrimp - SW Vase Red Mangroves