It is essential to carefully maintain water fountains for them to function optimally. A typical problem with fountains is that they tend to accumulate dirt and debris, so it is essential that you keep it free from this. Another factor is that water that is exposed to sunlight is prone to growing algae. Either sea salt, hydrogen peroxide, or vinegar can be mixed into the water to prevent this issue. There are those who like to use bleach, but that is dangerous to any animals that might drink or bathe in the water - so should therefore be avoided.
No more than three-four months should really go by without an extensive cleansing of a fountain. The first task is to get see this rid of all of the water. Next use mild soap and a soft sponge to clean the innner part of the reservoir. A good tip is to use a toothbrush if there are little hard-to-reach spots. Make sure all the soap is totally washed off.
Calcium and fresh water organisms could get inside the pump, so you should disassemble it to get it truly clean. To make it less strenuous, soak it in vinegar overnight before cleaning. If you want to remove build-up in your fountain, use rain water or mineral water versus tap water, as these don’t contain any elements that might stick to the inside of the pump.
Finally, be sure to have a quick look at your fountain every day and add water if you notice that the level is depleted. Allowing the water to reach below the pump’s intake level, can cause severe damage and even make the pump burn out - an undesired outcome!