Product review (5 stars): These filters do their job.
These filters are great.  I have to admit I hadn't changed my filter for awhile and it was pretty bad.  When I put the new filter in you could tell the difference by the amount of water that was gone the next morning after running it all night.  Before only about 1/2 the tank was used whereas with the new filter almost all of the tank is used.  Definitely works better when you change the filters regularly.  This also seemed like a good deal for the 2 pack.