Pool water clarity is dependent on two things: the effectiveness of the filter and the chemical balance in the pool. The pool’s filter provides 85% of the water clarity and the chemicals used to treat a pool add the other 15%. Chemicals or filters alone cannot keep a pool clear. If the filter media is old it may need replacing. If the pool ‘balance’ is wrong it needs fixing. The problem usually associated with a cloudy pool is a filter media filter. A D.E. filter may need a manual cleaning, a sand filter may need backwashing or replacement of the sand, a cartridge filter usually always requires replacement of the cartridges. If the pool water chemistry is okay, it’s time to perform maintenance on the filter.