Hayward Chlorinator CL200 O-Ring Needs Replacement Very Frequently

I have a Hayward Chlorinator CL200 for my above ground. I seem to have to go through 3-4 O-Rings per season. They all seem to lose their elasticity very quickly. I've used original Hayward rings, off market secondary rings, with lubrication and without lubrication. Is this just par for the course for this chlorinator? Do original Hayward rings last longer? It seems I might as well buy off market rings on eBay in bulk since they need replacement so often. Thanks, Dave