Please note that I am speaking of the Hayward CL-220 off line feeder.

The off line feeder is the basically the same as the in line model. Before many of our customers started getting SWCG systems, they were included on every pool the company I work for installed, as such, I've 'played' with hundreds of them. To be sure, they have problems (!) - but those are most probably minimized by not having them used as the only chlorine source. There are a lot of little parts that tend to break (the connectors for the hoses) regularly (yearly) and the lid o-ring can sometimes need to be replaced more than once a season On the plus side, they are incredibly easy to install, and if you use it as Al uses his, I doubt that you'll have the problems I've seen They do have a built in backflow preventer (which only occasionally sticks ), so a 'check valve' before it isn't necessary.

If you decide to go with one, remove the pucks when you're not using the unit - this alone will probably prevent most of the problems I've had to fix. If you have any other questions on what I've said, or want a little info on installation - I'll tell you what I know