Empty your fountain, rinse it and replace the water at least once a month. When it doubt, clean it! You'll be much happier in the long run.
Put a plastic tube on your pump and pump most of the water out. Pick up the base and dump out the rest of the water. If your fountain is inside, once most of the water is out, carry it to a utility sink or outside.
Hose off the base real well. Use a plastic brush or plastic scrub pad if needed.
Remove and clean your pump and filter.
Fill it back up with water and you're good to go.
Preventive Maintenance Tips
If you follow theses three pump rules your pump should
work well and live a long time:
Keep your water clean - change it frequently so debris doesn't get into the impeller.
While in operation, keep your pump submerged at all times - you really can't over fill your base, but if the water isn't high enough your pump may heat up and burn out.
Keep your pump clean inside and outside. If it has a filter, hose it off frequently and replace it when it either gets hard and nonporous or starts to fall apart after a number of months. If there's no filter, there's usually a strainer that needs to be removed and cleaned off.
If your pump fails to operate properly, the first thing to check is the impeller. If a piece of debris gets stuck under the impeller it will keep it from moving. Usually you can remove the debris with a hose or by pushing the impeller. You can avoid this problem by following the steps above. It also doesn't hurt to put the hose into the impeller area each time you change the water. Anything working its way in there will be forced out. Pumps have a one year warranty. Rarely do they fail during that time, but please keep your receipt and box -- just in case.
When you change your water, it's a good idea to put the hose on full force into the plastic tube that feeds water to the fountain. That way you will flush out any debris that may be working it's way through the tubing.
You may need to scrub it with a plastic scrub pad or brush. And if you've let it go too long you may need to give it a little bath with diluted bleach, but never use steel pads, Brillo, etc.