I love these filters and they seem to work great when you get a good one but this is the 3rd time I've bought one and when I open the package up the plastic housing is cracked or broken. The box's were all in mint condition with not even a crushed corner so that tells me it's a quality control issue from the factory. Luckily Fosters & Smith have excellent customer service and each time they send me a new one and a return shipping label for the old one so I'm not out any money it's just kinda inconvenient. This is 3 out of the 4 AC's I've bought that this has happened. Is this just my bad luck or a known issue?? After I get a good one I have zero complaints about these filters. The AC mini on my 10g has been going strong for over 10 years now with zero issues. They don't re prime themselves as easily as the Penguin/Emperor filters but overall a great filter.