http://www.brittline.com/2012/01/07/a-water-fountain-for-your-dog/
Most dogs love to drink running water, but in the past, this has been a difficult thing to supply your pet with. Recently however, a company by the name of Drinkwell has introduced a running water pet fountain that delivers running water throughout the day with the use of an electric motor. Drinkwell has a handful of different fountain models on the market today, but as a dog owner, you should only really consider two of the options.
First, there is the Drinkwell Platinum fountain, which is a good option for those owners of a small or medium sized dog. The Platinum is a revised version of Drinkwell’s first pet fountain, which is named the Original pet fountain. The Platinum model improved on two of the Original’s deficiencies, a lack of water capacity and troublesome cleaning issues. The Platinum model holds 168 ounces of water compared to only fifty ounces from the Original model. This is a huge improvement and makes the newer model a great fit for dogs. Since the pet fountains need to be cleaned frequently, Drinkwell also simplified the Platinum fountain for cleaning purposes. This will save you time and frustration with the fountain.
For larger dogs, Drinkwell has recently introduced the model they call the Drinkwell Big Dog fountain. It looks much like the Original and Platinum models, but is definitely super sized. With 2.25 gallons of water capacity (288 ounces), it’s a much better fit for large dogs. The bigger construction is also nice for large dogs because it means they don’t have to bend down quite as far to drink from the running water stream. You can expect to pay about ten dollars more for the Big Dog fountain compared to the Platinum model. If you have a medium or large dog in your household, it makes sense to opt for the bigger fountain considering the small price increase between the two.