In our shop, http://www.catfountains.etsy.com we offer both large and small capacity fountains and each has their virtues and their drawbacks. The purpose of this post is to address those issues so potential customers can make an educated decision on which size of cat fountain to buy.
I define a small capacity fountain as holding anywhere from 4 to 7 cups, a medium cat fountain holds from 8 to 12 cups and a large capacity holds upwards of 12 cups all the way up to 24 cups. Any fountain meant for a cat larger than this is disadvantageous, for a variety of reasons, discussed below.
The fountain below holds about 5+ cups. This fountain would need replenishing about every other day or so if for a single cat. If for two or more cats you would probably want to replenish it daily. It’s advantage is tha
t it is light weight so easy to transport when filled with water.
The next fountain is in the medium sized range, holding about 8 cups.
Still light weight but can go a few days without adding more water. This is about the size fountain my cat, Bijou has. I clean it once a week and it is very easy to work with.
At first we are tempted to think that the larger the fountain and greater the capacity the better but
this is only true if you have several animals and don’t want to be frequently replenishing. The disadvantage of a large cat fountain bowl for one or only a few animals is that because it doesn’t need replenishing often it may not receive the cleaning it needs when it needs it. After all if the fountain still has lots of water there is a temptation to just leave it but this is not the best practice when considering your cats’ health.
Any fountain, even the best of the ceramic cat fountains such as ours which are handmade of 100% food save stoneware and tested and proven glazes still need an occasional cleaning. Though the copper used in many of our fountains inhibits a lot of bacteria growth, water is the natural home of billions of organisms and if allowed to sit will eventually become distasteful to your cat. Generally, cleaning about once a week seems good, at least for Bijou who is a very clean, short-haired cat but with other breeds and more cats more frequent cleaning is probably in order – possibly about once every four days.
Because cleaning of these fountains (and do note, this is not true of the manufactured cat fountains such as the Drinkwell, and others), is so simple, requiring about 3 or 4 minutes, cleaning every few days is not a hardship.
Below is one of our large capacity fountains. 
The primary downside to such a large capacity fountain is that it is really heavy. Empty it weighs 15.5 lbs – not a problem, but filled to its two gallon capacity it weighs 40 lbs. Ok for many but too much for others.
As suggested, the other potential drawback of a large capacity fountain is that it may not get the frequency of cleaning that is optimal for clear, clean and healthful cat drinking water. There is a reluctance to picking it up and carrying it to the sink and as the water will will continue to look perfectly fine long after it has become not as appealing to your cat – this can be disadvantageous. Of course, if you keep it next to the sink this is not an issue, and, you can always scoop out some of the water before lifting so this can still work as a cat fountain.
As an indoor fountain for home decor, cleaning the fountain is much less of an issue and needs to be done much more infrequently and that was the real intend behind the making of this fountain. It is being offered as a cat fountain but will probably sell to someone who wants it for its beauty.
cat-fountains.com 