The Fresh Flow Fountain is generally a pretty good product, but the filters are fairly expensive. And, I've had quite a bit of trouble finding them.

Wal-Mart originally carried the fountains and filters, but stopped carrying these particular ones. PetSmart usually has them, but the filters are hard to find because they're often located in weird places. (Instead of with the fountains, the LOGICAL place.)

The filters do seem to keep the water fresher longer. I usually have to clean hair out of the pump once or twice before I have to change a filter. I can usually get a few weeks out of each filter.

Petmate has at least come out with a 6 pack.

Pros: Works pretty well at keeping water fresh

Cons: Filters are hard to find and expensive

Works well, keeps water fresh. best if you don't have many dogs or you'll have to change the filter more frequently

Pros: long lasting

Cons: better if you only have one dog

These filters do what they need to do and that is to filter the water and keep it fresh and clean. We change our filter anywhere between 30-45 days. We try to extend the life of them by rinsing them out when we change the water and that seems to help.

Pros: Keeps water fresh

Cons: somewhat expensive

This is a good product. the only drawback is when it does need cleaning it takes a few minutes. Overall it is worth it.

Pros: Keeps water clean

Cons: cleaning it

This filter keeps my cat's water fountain fresh from contaminants. It does need to be replaced quite often, which makes it more expensive than I'd like. It is an item I use to keep my cats healthy.

Pros: Keeps water fresh

Cons: Not cheap