Im considering one of the budget option SWG,,,Circupool,Purline,Calimar......But I have a question. So they claim Hayward cells or the discount replacement Hayward Cells are not compatible. Why is that, that appear to be the same thing? My concern is, using Circupool as an example. When its time for a replacement cell, it seem the only option is the Circupool replacement. Looking long term will these budget brands be around? Are the cells really compatible, but they just can't say they are?