Regular cleaning of your investment is recommended, the frequency depends on the environment. A marine environment and one which collects large amounts of dust & grime will require more frequent washing. Cleaning is relatively easy as you just need to remove loose debris with a soft cloth or sponge and a neutral detergent then rinse off with clean water.
It is also advisable to avoid spraying your powder coated fence with chemical sprays.
Do not leave wet towels on your pool fence as constant contact of the chlorides and salts will start the corrosion process.
As a general rule cleaning of your fence every 6 months should be sufficient to remove the deposits and restore the finish.