White Cloudy Water:
White cloudiness is usually the result of a bacteria bloom. Keep a careful check on ammonia levels, if the bacteria is a result on bacteria die off, you may experience increased ammonia levels and your tank maybe recycling. Bacteria also consume oxygen, so just as with an algae bloom, you want to increase circulation while treating the tank.
Causes:
Medical treatment of your aquarium that has destroyed the bacteria colonies. (Not all medicines will destroy the bacteria but some will).
As in algae, high nutrient levels can also trigger a bacteria bloom (In this case, they are feeding on the excess nutrients)
Sometimes the cleaning of all filters at once, or the changing of the gravel can trigger a bacteria bloom, due to the removal of bacterial colonies that had settled on the filter media or substrate.
Solutions
As with algae, you need to control the nutrient level of the tank. Once you control this, the bacteria bloom will usually go away on it's own.
If your tank is recycling and filled with expensive fish, you may want to consider the use of zeolites to absorb the ammonia while your tank finishes the cycle. This will extend the time that the tank needs to complete the cycle though.
http://www.drhelm.com/aquarium/cloudy%20water.html