New to the posts but I have been reading a lot of articles and posts here that have been so helpful. We are brand new pool owners as of 6 weeks ago, as we bought a house with an in-ground pool. We know zero about pools and had no idea what the white cylinder attached to the filter was. I thought it was an extra filter of sorts but nope, now I know it's and inline chlorinator. I don't think the previous owner used it as they left behind a duck floaty and a ton of tablets. I've been using liquid chlorine and thanks to this site, we'll continue to use that over the chlorinator or the float tabs!