"Get Rid Of The Grime.
Dirt and debris wear on the fountain's surface. Once a month, bail out gritty water (or siphon it off with a wet-dry vac); then wipe the interior with a soft cloth or sponge. Scrub off buildup with vinegar and a soft bristled nylon brush; wipe clean and refill.
Put On Socks.
Slip an old nylon stocking over the pump and its intake to keep out stray dirt.
Each time you refresh the water supply, add a clarifier to deter algae growth and a scale and stain remover, following the label directions on dosage (it depends on your fountain's capacity). Double the normal amount if you notice algae or scale that persists. In warmer months, when algae grows more readily, add a time-release algaecide in tablet form about once every three weeks.
Don't Let It Run Dry.
Your pump could overheat if the water level's too low, so keep an eye on it, especially if you've had a string of hot, dry days.
NEVER USE Chlorine.
Fountain pumps aren't designed to work with concentrated levels of chlorine, but if an algae bloom won't die down, add 1/4 cup of distilled vinegar for every 5 gallons of water, and run the pump overnight so it circulates long enough to disinfect the entire system". You can also add shiny copper pennies to oxidize the water and fight algae growth.
DISHNER, Jackie. "Five Tips To Keep Your Fountain Running." This Old House. Thisoldhouse.com, n.d. Web. 02 Apr. 2014. <http://www.thisoldhouse.com/toh/article/0%2C%2C20209545%2C00.html>.