Green algae is one of the most common problems in maintaining clear pool water. Algae can grow overnight and is extremely difficult to get rid of. It is the result of water that has been left unbalanced with inadequate filtration, water temperature and sunlight and the presence of nitrates in the water. Saltwater chlorinators turn salt into liquid chlorine to keep your pool clean. Green water in a saltwater pool usually means the filter is not running long enough to clear the water of the free radicals.
Test your pool water to ensure you have the proper pH. Get a water sample from your pool. Try to get water from below the water's surface. Dip the test strip into the water and hold it for fifteen seconds. Remove the strip from the sample and compare the colour to the colour on the test bottle. Different test kits use different colours. If your pool's pH is off, it will be harder to maintain the effectiveness of chlorine.
Add the necessary amounts of salt in your chlorinator to increase the pH and the chlorine in your pool. If you have already added the proper amounts, your chlorinator may not be working effectively. You may have to have it checked by a licensed pool repairman.
Shock the pool with enough chlorine to raise the free chlorine levels to 10 ppms. Begin with 0.454 to 0.907 Kilogram. You can add more shock but you can't take it out. Check the labels or ask your pool specialist to ensure the products you are using are safe for saltwater pools.
Scrub the sides and bottom of your pool to loosen any algae that has attached itself.
Run your salt chlorinator continuously until the water clears.
Vacuum up any dead algae that may have settled on the bottom of the pool. If possible, vacuum the water to waste so that the dead algae is removed from the pool
You can take your pool water to nearly any pool store and they will test the water for you. Treat the first signs of algae immediately. The sooner you act, the easier it will be.