I tried this product recommended by my pool service and it was a disaster. After application the pool turned cloudy the next day and by the afternoon was green with algae. Additional problems incurred were the suction flow through the skimmer was impaired for two days and I had to run a hose in the line to give me brief periods of suction. Then had to go through a step by step check to see why I lost suction. Oen and check the trap, examine the valves until finally backwashing the filter proved to be effective which adds cleaning and recharging the filter to the correction process. If this is not a convincing reason not to buy this product check the Amazon and Leslies reviews on the product