Kittykrazee,
When you say the o-ring on the hard tank, do you mean on the atomizer? The elips has the o-ring on the atomizer, but there is a knock-off of the elips usually branded the LSK. These units are not compatible. If you can sent me a picture to
support@ovaleusa.com or just post one here then I could let you know if it is an elips or not. Our elips has gotten some misplaced bad reviews due to these off brand remakes. Please let me know and perhaps I can help out in another way if the unit you have is indeed a copycat. All of our products are highly branded with the Ovale logo.